Make target branch a URL parameter
Description
For a project with several main branches. Kind of like GitLab CE where we have stable branches of older versions of GitLab where we merge security fixes.
If a developer is submitting MR's to a different branch all day long, it would end up saving them some time if they could just change a URL parameter when they load the MR page and the target-branch is filled in correctly.
Proposal
Currently we have https://gitlab.host.com/mygroup/myrepo/merge_requests/new?merge_request%5Bsource_branch%5D=some_branch
Except that master at the end would be whatever the default branch of the repository is set to.
This should still behave exactly as it currently does if the user just pastes it into a browser without editing it first
Links / references
Here is the ZenDesk Ticket where a subscriber requested it