Add explicit support for Django 5.2a1 to build matrix (#988)

Author: jieter

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
     strategy:
       matrix:
         python-version: [3.9, "3.10", 3.11, 3.12] # 3.13 can be supported if lxml supports 3.13
-        django-version: [4.2, 5.0, 5.1, master]
+        django-version: [4.2, 5.0, 5.1, "5.2a1", "master"]
         exclude:
             # Django 4.2
             - python-version: 3.12
@@ -34,8 +34,16 @@ jobs:
             - python-version: 3.9
               django-version: 5.1
 
-            # master
+            # Django 5.2
             - python-version: 3.9
+              django-version: 5.2a1
+
+            # Django master
+            - python-version: 3.9
+              django-version: master
+            - python-version: 3.10
+              django-version: master
+            - python-version: 3.11
               django-version: master
 
     steps: