Big Bang Bot: Update CODEOWNERS

Action	User	Reason
Remove	@montgomery.marcus	user's employment dates are not longer active
Add	@michael.mendez	user is in the team charter for this repo but not in the current repo's CODEOWNERS
Remove	@kipten	user is not defined in the team charter for this repository
Remove	@cwilliams68067	user is not defined in the team charter for this repository
Remove	@wyatt.fry	user is not defined in the team charter for this repository
Remove	@lgomez2	user is not defined in the team charter for this repository

These changes are automatically generated based on the state stored in the Team Charter Mission Team manifest. If these changes are not expected, please refer to the Updating Team Charter manifest docs.