python310Packages.djangorestframework-guardian: mark broken with django4

and point people to the guardian2 fork.

pkgs/development/python-modules/djangorestframework-guardian/default.nix

@@ -1,6 +1,7 @@
 { lib
 , buildPythonPackage
 , fetchFromGitHub
+, django
 , django-guardian
 , djangorestframework
 }:
@@ -37,5 +38,7 @@ buildPythonPackage rec {
     homepage = "https://github.com/rpkilby/django-rest-framework-guardian";
     license = licenses.bsd3;
     maintainers = with maintainers; [ ];
+    # unmaintained, last compatible version is 3.x, use djangorestframework-guardian2 instead
+    broken = lib.versionAtLeast django.version "4";
   };
 }