mailmap: Fix mypy errors with django-stubs 5.0.2

requirements-test.txt

 beautifulsoup4
 decorator  # dependency of swh.core[http]
 djangorestframework-stubs
-django-stubs != 4.2.2
+django-stubs >= 5.0.2
 django-test-migrations
 hypothesis
 pytest >= 8.1

swh/web/mailmap/management/commands/sync_mailmaps.py

-# Copyright (C) 2022  The Software Heritage developers
+# Copyright (C) 2022-2024  The Software Heritage developers
 # See the AUTHORS file at the top-level directory of this distribution
 # License: GNU Affero General Public License version 3, or any later version
 # See top-level LICENSE file for more information
 
+from __future__ import annotations
+
 import psycopg2
 import psycopg2.extensions
 from psycopg2.extras import execute_values
@@ -46,7 +48,7 @@ class Command(BaseCommand):
     def disable_mailmaps(
         self,
         storage_db: psycopg2.extensions.connection,
-        mailmaps: "QuerySet[UserMailmap]",
+        mailmaps: QuerySet[UserMailmap, UserMailmap],
     ):
         """Return the SQL to disable a set of mailmaps"""
 
@@ -59,7 +61,7 @@ class Command(BaseCommand):
     def refresh_mailmaps(
         self,
         storage_db: psycopg2.extensions.connection,
-        mailmaps: "QuerySet[UserMailmap]",
+        mailmaps: QuerySet[UserMailmap, UserMailmap],
     ):
         execute_values(
             storage_db.cursor(),