Pin Django release in dev dependencies (#885)

Django 6.0 has some runtime changes that would fail `stubtest`. Pin version `5.2.*`

Author: intgr

pyproject.toml

@@ -46,6 +46,7 @@ dev = [
   "pytest==9.0.2",
   "pytest-mypy-plugins==3.2.0",
   "djangorestframework==3.16.1",
+  "django==5.2.*",
   "types-pytz==2025.2.0.20251108",
   "types-requests==2.32.4.20250913",
   "types-urllib3==1.26.25.14",