chore: set CODEOWNER to @googleapis/python-core-client-libraries (#1652)

* chore: set CODEOWNER to @googleapis/python-core-client-libraries

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

* 🦉 Updates from OwlBot post-processor

See https://github.com/googleapis/repo-automation-bots/blob/main/packages/owl-bot/README.md

---------

Co-authored-by: Owl Bot <gcf-owl-bot[bot]@users.noreply.github.com>

Author: parthea

packages/gapic-generator/.github/CODEOWNERS

@@ -1,8 +1,4 @@
 # Code owners file.
 # This file controls who is tagged for review for any given pull request.
 
-# For syntax help see:
-# https://help.github.com/en/github/creating-cloning-and-archiving-repositories/about-code-owners#codeowners-syntax
-
-* @googleapis/actools-python @googleapis/yoshi-python
-*.yaml @googleapis/yoshi-python @googleapis/actools-python
+*                         @googleapis/python-core-client-libraries