Add django to matrix to fix tests

Author: Jacob Colyvan

.github/workflows/ci.yml

@@ -13,10 +13,13 @@ jobs:
         include:
           - python-version: "3.10"
             wagtail-version: "6.3"
+            django-version: "4.2"
           - python-version: "3.11"
             wagtail-version: "7.0"
+            django-version: "5.1"
           - python-version: "3.12"
             wagtail-version: "7.1"
+            django-version: "5.1"
 
     steps:
       - uses: actions/checkout@v4
@@ -31,6 +34,7 @@ jobs:
       - name: Install dependencies
         run: |
           python -m pip install --upgrade pip
+          pip install "Django~=${{ matrix.django-version }}.0"
           pip install wagtail==${{ matrix.wagtail-version }}
           pip install .[testing,dev]