Mark model renaming as irreversible for now (#22248)

django/db/migrations/operations/models.py

@@ -98,6 +98,8 @@ class RenameModel(Operation):
     Renames a model.
     """
 
+    reversible = False
+
     def __init__(self, old_name, new_name):
         self.old_name = old_name
         self.new_name = new_name