release: Update package.xml version to 1.1.1

package.xml

 <?xml version="1.0"?>
 <package format="3">
   <name>ndcurves</name>
-  <version>1.1.0</version>
+  <version>1.1.1</version>
   <description>
       A template-based Library for creating curves of arbitrary order and dimension
   </description>