ci: run tests also with Python 3.12

The `assertEquals` unittest alias has been deprecated in 3.2 and removed
in 3.12, so we change it to `assertEqual`.

Closes: #411

.github/workflows/django-tests.yml

@@ -13,7 +13,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.11"]
+        python-version: ["3.11", "3.12"]
     steps:
     - uses: actions/checkout@v3
     - name: Set up Python ${{ matrix.python-version }}

apis_core/apis_metainfo/test_models.py

@@ -14,9 +14,9 @@ def setUp(cls):
     def test_root_object(self):
         rfoo = RootObject.objects.get(name="foo")
         rnone = RootObject.objects.get(name="")
-        self.assertEquals(str(rfoo), "foo")
-        self.assertEquals(str(rnone), "no name provided")
+        self.assertEqual(str(rfoo), "foo")
+        self.assertEqual(str(rnone), "no name provided")
 
     def test_uri(self):
         ufoo = Uri.objects.create()
-        self.assertEquals(str(ufoo), "None")
+        self.assertEqual(str(ufoo), "None")