Support `allowed_to_unprotect` field in branch protection resource
Feature Description
The gitlab_branch_protection
resource is missing the allowed_to_unprotect
field.
The goal is to implement this to align with the upstream API.
While at it, it may also make sense to double check the branch protection data sources if they are aligned with upstream. (I quickly checked and I'm not sure if the upstream docs example is complete - it may make sense to quickly manually try what the response is.)
Edited by Timo Furrer