update github workflow to use django 4.2

Author: anthonyp97

.github/workflows/main.yml

@@ -20,7 +20,7 @@ jobs:
     strategy:
       matrix:
         python-version: [ "3.7", "3.8", "3.9", "3.10" ]
-        django-version: [ "3.2" ]
+        django-version: [ "4.2" ]
     steps:
       # Checks-out the  repository.
       - uses: actions/checkout@v2