Fix Merge Request reviewer list for protected branch
Created by: rhtyd
By setting a branch as protected in gitlab (commits->branches), we restrict push on those branches only by the masters.
The issue that needs to be addressed here is that on a merge request for a selected target branch say 'master' gitlab should only show the project masters in the reviewer drop down list. And only masters should be able to merge a merge request and not any selected reviewer for a protected branch.