chore: add Python 3.14 to test matrix

tox.ini

@@ -6,7 +6,7 @@ envlist =
     py{39,310,311,312}-django42
     py{310,311,312}-django50
     py{310,311,312,313}-django51
-    py{310,311,312,313}-django52
+    py{310,311,312,313,314}-django52
     lint
     coverage
 
@@ -17,6 +17,7 @@ python =
     3.11: py311
     3.12: py312
     3.13: py313
+    3.14: py314
 
 [testenv]
 allowlist_externals = ./manage.py