python310Packages.django-reversion: add changelog to meta

pkgs/development/python-modules/django-reversion/default.nix

···
   meta = with lib; {
     description = "An extension to the Django web framework that provides comprehensive version control facilities";
     homepage = "https://github.com/etianen/django-reversion";
+    changelog = "https://github.com/etianen/django-reversion/blob/v${version}/CHANGELOG.rst";
     license = licenses.bsd3;
     maintainers = with maintainers; [ ];
   };