updating cibuildwheel version

Author: Sam Rensenhouse

.github/workflows/build-wheels.yml

@@ -47,7 +47,7 @@ jobs:
         if: startsWith(matrix.os, 'windows')
 
       - name: Install cibuildwheel
-        run: python -m pip install cibuildwheel==2.2.0a1
+        run: python -m pip install cibuildwheel==2.3.1
 
       - name: Build wheels
         run: python -m cibuildwheel --output-dir wheelhouse owa-epanet