Fix exclude matrix

Author: mikemanger

.github/workflows/ci.yml

@@ -76,12 +76,15 @@ jobs:
           - "5.0"
           - "5.1"
         exclude:
+          # See https://docs.djangoproject.com/en/dev/faq/install/#what-python-version-can-i-use-with-django
           - django-version: "4.2"
-            python-version: ["3.13"]
+            python-version: "3.13"
           - django-version: "5.0"
-            python-version: ["3.9", "3.13"]
+            python-version: "3.9"
+          - django-version: "5.0"
+            python-version: "3.13"
           - django-version: "5.1"
-            python-version: ["3.9"]
+            python-version: "3.9"
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4