templates: switch to main branch

Author: julianoes

other/templates/py/file.j2

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 # DO NOT EDIT! This file is auto-generated from
-# https://github.com/mavlink/MAVSDK-Python/tree/master/other/templates/py
+# https://github.com/mavlink/MAVSDK-Python/tree/main/other/templates/py
 from ._base import AsyncBase
 from . import {{ plugin_name.lower_snake_case }}_pb2, {{ plugin_name.lower_snake_case }}_pb2_grpc
 from enum import Enum