Expand set of Python versions to run tests against (#467)

Author: pietern

.github/workflows/push.yml

@@ -11,7 +11,13 @@ jobs:
     strategy:
       max-parallel: 4
       matrix:
-        python-version: [ 2.7, 3.6 ]
+        python-version:
+          - '2.7'
+          - '3.6'
+          - '3.7'
+          - '3.8'
+          - '3.9'
+          - '3.10'
         os: [ ubuntu-latest ]
     env:
       OS: ${{ matrix.os }}