chore: add dragonfly-maintainers as codeowners alongside approvers (#4684)

Signed-off-by: Gaius <gaius.qi@gmail.com>

Author: gaius-qi

.github/CODEOWNERS

@@ -1,7 +1,2 @@
-# A CODEOWNERS file uses a pattern that follows the same rules used in gitignore files.
-# The pattern is followed by one or more GitHub usernames or team names using the
-# standard @username or @org/team-name format. You can also refer to a user by an
-# email address that has been added to their GitHub account, for example user@example.com
-
-*                                          @dragonflyoss/dragonfly-approvers
+*                                          @dragonflyoss/dragonfly-maintainers @dragonflyoss/dragonfly-approvers
 .github                                    @dragonflyoss/dragonfly-maintainers