Add Or Update Team Membership For User (legacy)

**Deprecation Notice:** This endpoint route is deprecated and will be removed from the Teams API. We recommend migrating your existing code to use the new [Add or update team membership for a user](https://docs.github.com/[email protected]/rest/teams/members#add-or-update-team-membership-for-a-user) endpoint. Team synchronization is available for organizations using GitHub Enterprise Cloud. For more information, see [GitHub's products](https://docs.github.com/[email protected]/github...