chore: Update CODEOWNERS to reflect new teams for auth (#16547)

Author: parthea

.github/CODEOWNERS

@@ -4,4 +4,4 @@
 # Default owner for all directories not owned by others
 *                                             @googleapis/cloud-sdk-python-team @googleapis/cloud-sdk-librarian-team
 
-/packages/google-auth/                        @googleapis/cloud-sdk-python-team @googleapis/cloud-sdk-librarian-team @googleapis/googleapis-auth @googleapis/aion-team
+/packages/google-auth/                        @googleapis/cloud-sdk-python-team @googleapis/cloud-sdk-librarian-team @googleapis/cloud-sdk-auth-team @googleapis/aion-team