Run tests also on Python3.10 (#88)

Author: dweindl

.github/workflows/ci_tests.yml

@@ -11,7 +11,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [3.7, 3.8, 3.9]
+        python-version: [3.7, 3.8, 3.9, "3.10"]
 
     steps:
     - name: Check out repository