Update file requirements.txt

requirements.txt

@@ -51,7 +51,8 @@ MarkupSafe==2.1.1
 matplotlib==3.5.2
 matplotlib-inline==0.1.3
 MDAnalysis==2.2.0
-mdtraj==1.9.7
+#mdtraj==1.9.7
+mdtraj @ git+https://github.com/mdtraj/mdtraj@master # fix for macOS (to be modified by a stable release of mdtraj)
 mistune==0.8.4
 mmtf-python==1.1.3
 mrcfile==1.4.2