Allow commits from users who can commit to the target branch by default

Problem to solve

When forking a project and submitting a contribution upstream, it is very useful to have source project maintainers be able to make changes to the merge request from the fork in order to speed up the contribution process.

However, in order to allow this, the Allow commits from members who can merge to the target branch checkbox has to be checked when the MR is created. Often times, contributors will forget to check this box, which slows down the contribution process.

Further details

Some workflows call for maintainers of the source project to rebase for someone or fix a typo before merging without losing any time having a feedback loop. The problem is that people usually forget to tick the "Allow commits from members who can merge to the target branch." checkbox.

Proposal

Add a "Allow contributions from members who can merge to the target branch." checkbox in Settings/Merge Request.

Change the default setting for Allow commits from members who can merge to the target branch to enabled. Users who don't want to allow this can simply untick the setting when submitting the MR