Update django.yml

Author: FrankQixiangGao

.github/workflows/django.yml

@@ -13,7 +13,7 @@ jobs:
     strategy:
       max-parallel: 4
       matrix:
-        python-version: [3.7, 3.8, 3.9]
+        python-version: [3.9]
 
     steps:
     - uses: actions/checkout@v3