Add support for Python versions 3.10 and 3.11

Author: bartsanchez

.github/workflows/unit_tests.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python: [3.7, 3.8, 3.9]
+        python: [3.7, 3.8, 3.9, 3.10, 3.11]
         django_version: [22, 30, 40]
         exclude:
           - python: 3.7