fix final diff checker for django 4 point versions

Author: hjwp

tests/test_chapter_working_incrementally.py

@@ -57,7 +57,7 @@ def test_listings_and_commands_and_output(self):
             print(self.pos)
             self.recognise_listing_and_process_it()
 
-        self.check_final_diff(ignore=["moves", "Generated by Django 4.2."])
+        self.check_final_diff(ignore=["moves", "Generated by Django 4."])
         self.assert_all_listings_checked(self.listings)