ci: Add a workflow that use Pixi and remove conda workflow

.github/workflows/conda/environment_all.yml

-name: eigenpy
-channels:
-  - conda-forge
-dependencies:
-  - eigen
-  - cmake
-  - numpy
-  - pkg-config
-  - boost
-  - ccache
-  - cxx-compiler
-  - ninja
-  - scipy

.github/workflows/macos-linux-conda.yml

-name: CI - OSX/Linux via Conda
-
-on:
-  push:
-    paths-ignore:
-      - 'doc/**'
-      - '.gitlab-ci.yml'
-      - '.gitignore'
-      - '*.md'
-      - 'LICENSE'
-      - 'colcon.pkg'
-      - '.pre-commit-config.yaml'
-  pull_request:
-    paths-ignore:
-      - 'doc/**'
-      - '.gitlab-ci.yml'
-      - '.gitignore'
-      - '*.md'
-      - 'LICENSE'
-      - 'colcon.pkg'
-      - '.pre-commit-config.yaml'
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: true
-
-jobs:
-  eigenpy-conda:
-    name: ${{ matrix.os }} - Python ${{ matrix.python-version }} ${{ matrix.build_type }} ${{ matrix.cxx_options }}
-    runs-on: ${{ matrix.os }}
-    env:
-      CCACHE_BASEDIR: "${GITHUB_WORKSPACE}"
-      CCACHE_DIR: "${GITHUB_WORKSPACE}/.ccache"
-      CCACHE_COMPRESS: true
-      CCACHE_COMPRESSLEVEL: 6
-
-    strategy:
-      fail-fast: false
-      matrix:
-        os: ["ubuntu-latest", "macos-latest","macos-14"]
-        cxx_options: ['', '-mavx2']
-        build_type: [Release, Debug]
-        python-version: ["3.8", "3.12"]
-
-        exclude:
-          - build_type: Debug
-            cxx_options: -mavx2
-            os: macos-latest
-          - build_type: Release
-            cxx_options: -mavx2
-            os: macos-latest
-          - build_type: Debug
-            cxx_options: -mavx2
-            os: macos-14
-          - build_type: Release
-            cxx_options: -mavx2
-            os: macos-14
-
-    steps:
-    - uses: actions/checkout@v4
-      with:
-        submodules: recursive
-
-    - uses: actions/cache@v4
-      with:
-        path: .ccache
-        key: ccache-macos-linux-conda-${{ matrix.os }}-${{ matrix.build_type }}-${{ matrix.cxx_options }}-${{ matrix.python-version }}-${{ github.sha }}
-        restore-keys: ccache-macos-linux-conda-${{ matrix.os }}-${{ matrix.build_type }}-${{ matrix.cxx_options }}-${{ matrix.python-version }}-
-
-    - uses: conda-incubator/setup-miniconda@v3
-      if: matrix.os != 'macos-14'
-      with:
-        activate-environment: eigenpy
-        auto-update-conda: true
-        environment-file: .github/workflows/conda/environment_all.yml
-        python-version: ${{ matrix.python-version }}
-        auto-activate-base: false
-
-    - uses: conda-incubator/setup-miniconda@v3
-      if: matrix.os == 'macos-14'
-      with:
-        activate-environment: eigenpy
-        auto-update-conda: true
-        environment-file: .github/workflows/conda/environment_all.yml
-        python-version: ${{ matrix.python-version }}
-        auto-activate-base: false
-        installer-url: https://github.com/conda-forge/miniforge/releases/download/23.11.0-0/Mambaforge-23.11.0-0-MacOSX-arm64.sh
-
-    - name: Build EigenPy
-      shell: bash -el {0}
-      run: |
-        conda list
-        echo $CONDA_PREFIX
-
-        mkdir build
-        cd build
-
-        cmake .. \
-          -G "Ninja" \
-          -DCMAKE_INSTALL_PREFIX=$CONDA_PREFIX \
-          -DCMAKE_CXX_COMPILER_LAUNCHER=ccache \
-          -DPYTHON_EXECUTABLE=$(which python3) \
-          -DGENERATE_PYTHON_STUBS=ON \
-          -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} \
-          -DCMAKE_CXX_FLAGS=${{ matrix.cxx_options }} \
-          -DCMAKE_CXX_STANDARD=11
-        cmake --build . -j3
-        ctest --output-on-failure
-        cmake --install .
-
-    - name: Test packaging
-      shell: bash -el {0}
-      run: |
-        cmake -B test-packaging \
-          -S unittest/packaging/cmake \
-          -G "Ninja" \
-          -DPYTHON_EXECUTABLE=$(which python3)
-
-    - name: Configure hpp-fcl
-      shell: bash -el {0}
-      run: |
-        conda install -c conda-forge octomap assimp qhull
-
-        git clone https://github.com/humanoid-path-planner/hpp-fcl.git --recursive
-        cd hpp-fcl
-        mkdir build && cd build
-        cmake .. \
-          -G "Ninja" \
-          -DCMAKE_INSTALL_PREFIX=$CONDA_PREFIX \
-          -DCMAKE_BUILD_TYPE=Release \
-          -DBUILD_TESTING_SCIPY=ON \
-          -DPYTHON_EXECUTABLE=$(which python3)
-
-    - name: Uninstall EigenPy
-      shell: bash -el {0}
-      run: |
-        cd build
-        cmake --build . --target uninstall
-
-
-  check:
-    if: always()
-    name: check-macos-linux-conda
-
-    needs:
-    - eigenpy-conda
-
-    runs-on: Ubuntu-latest
-
-    steps:
-    - name: Decide whether the needed jobs succeeded or failed
-      uses: re-actors/alls-green@release/v1
-      with:
-        jobs: ${{ toJSON(needs) }}

.github/workflows/windows-conda.yml → .github/workflows/macos-linux-windows-pixi.yml

-name: CI - Windows via Conda
+name: CI - MacOS/Linux/Windows via Pixi
 
 on:
   push:
@@ -24,7 +24,8 @@ concurrency:
   cancel-in-progress: true
 
 jobs:
-  build:
+  eigenpy-pixi:
+    name: ${{ matrix.os }} - Env ${{ matrix.environment }} ${{ matrix.build_type }} ${{ matrix.cxx_options }} ${{ matrix.compiler }}
     runs-on: ${{ matrix.os }}
     env:
       CCACHE_BASEDIR: "${GITHUB_WORKSPACE}"
@@ -35,8 +36,26 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-          os: [windows-latest]
-          compiler: ["cl", "clang-cl"]
+        os: [ubuntu-latest, macos-latest, macos-13]
+        environment: [all, all-py39]
+        build_type: [Release, Debug]
+        cxx_options: ['', '-mavx2']
+
+        exclude:
+          - os: macos-latest
+            cxx_options: '-mavx2'
+          - os: macos-13
+            cxx_options: '-mavx2'
+
+        include:
+          - os: windows-latest
+            environment: all
+            cxx_options: ''
+            build_type: Release
+          - os: windows-latest
+            environment: all-clang-cl
+            cxx_options: ''
+            build_type: Release
 
     steps:
     - uses: actions/checkout@v4
@@ -46,86 +65,29 @@ jobs:
     - uses: actions/cache@v4
       with:
         path: .ccache
-        key: ccache-windows-conda-${{ matrix.compiler }}-${{ matrix.os }}-${{ github.sha }}
-        restore-keys: ccache-windows-conda-${{ matrix.compiler }}-${{ matrix.os }}-
+        key: ccache-macos-linux-windows-pixi-${{ matrix.os }}-${{ matrix.build_type }}-${{ matrix.cxx_options }}-${{ matrix.environment }}-${{ github.sha }}
+        restore-keys: ccache-macos-linux-windows-pixi-${{ matrix.os }}-${{ matrix.build_type }}-${{ matrix.cxx_options }}-${{ matrix.environment }}-
 
-    - uses: conda-incubator/setup-miniconda@v3
+    - uses: prefix-dev/setup-pixi@v0.8.1
       with:
-        activate-environment: eigenpy
-        auto-update-conda: true
-        environment-file: .github/workflows/conda/environment_all.yml
-        python-version: "3.10"
-        auto-activate-base: false
+        pixi-version: v0.31.0
+        cache: true
+        environments: ${{ matrix.environment }}
 
-    - name: Build Eigenpy
-      shell: cmd /C CALL {0}
+    - name: Build EigenPy [MacOS/Linux/Windows]
       env:
-        CC: ${{ matrix.compiler }}
-        CXX: ${{ matrix.compiler }}
+        CMAKE_BUILD_PARALLEL_LEVEL: 2
+        EIGENPY_BUILD_TYPE: ${{ matrix.build_type }}
+        EIGENPY_CXX_FLAGS: ${{ matrix.cxx_options }}
       run: |
-        call conda list
-
-        mkdir build
-        pushd build
-        cmake ^
-          -G "Ninja" ^
-          -DCMAKE_INSTALL_PREFIX=%CONDA_PREFIX%\Library ^
-          -DCMAKE_CXX_COMPILER_LAUNCHER=ccache ^
-          -DCMAKE_BUILD_TYPE=Release ^
-          -DGENERATE_PYTHON_STUBS=ON ^
-          -DPYTHON_SITELIB=%CONDA_PREFIX%\Lib\site-packages ^
-          -DPYTHON_EXECUTABLE=%CONDA_PREFIX%\python.exe ^
-          ..
-        if errorlevel 1 exit 1
-
-        :: Build
-        cmake --build . -j3
-        if errorlevel 1 exit 1
-
-        :: Testing
-        ctest --output-on-failure
-        if errorlevel 1 exit 1
-
-        :: Install
-        cmake --install .
-
-        :: Test Python import
-        cd ..
-        python -c "import eigenpy"
-        if errorlevel 1 exit 1
-
-        :: Test packaging
-
-        cmake -B test-packaging -S unittest/packaging/cmake ^
-          -G "Ninja" ^
-          -DPYTHON_EXECUTABLE=%CONDA_PREFIX%\python.exe
-        if errorlevel 1 exit 1
-
-        :: Configure hpp-fcl
-        conda install -c conda-forge octomap assimp qhull
-        git clone --recursive https://github.com/humanoid-path-planner/hpp-fcl.git
-        pushd hpp-fcl
-        mkdir build
-        pushd build
-        cmake ^
-          -G "Ninja" ^
-          -DCMAKE_INSTALL_PREFIX=%CONDA_PREFIX%\Library ^
-          -DCMAKE_BUILD_TYPE=Release ^
-          -DPYTHON_EXECUTABLE=%CONDA_PREFIX%\python.exe ^
-          ..
-        cd ..
-        if errorlevel 1 exit 1
-
-        :: Uninstall
-        cmake --build . --config Release --target uninstall
-        if errorlevel 1 exit 1
+        pixi run -e ${{ matrix.environment }} test
 
   check:
     if: always()
-    name: check-windows-conda
+    name: check-macos-linux-windows-pixi
 
     needs:
-    - build
+    - eigenpy-pixi
 
     runs-on: Ubuntu-latest