ci: Add Python 3.12 to test matrix and streamline tox.ini

This commit updates the project's continuous integration and local testing configurations to include Python 3.12.

Key changes include:
- **GitHub Actions (`.github/workflows/test.yml`):**
    - Added Python 3.12 to the test matrix.
    - Reordered Django versions in the test matrix for consistency.
- **Tox configuration (`tox.ini`):**
    - Simplified the test environment definitions to use a matrix-style approach (`d{52, 42}-py{313, 312, 311}`). This change aligns the local testing environments with the updated Python and Django versions supported in the CI workflow, making the configuration more concise and maintainable.

Author: saxix

.github/workflows/test.yml

@@ -40,8 +40,8 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        django: [ "52", "42"]
-        python: [ "3.13", "3.11" ]
+        django: [ "42", "52"]
+        python: [ "3.11", "3.12", "3.13" ]
 
     env:
       CELERY_BROKER_URL: redis://redis:6379/0

tox.ini

@@ -8,8 +8,7 @@ env_list =
     docs
     d{52, 42, 32}-type
     pkg_meta
-    d{42}-py{311}
-    d{52}-py{313}
+    d{52, 42}-py{313, 312, 311}
 skip_missing_interpreters = true
 
 [testenv]