MergeRequests API option to mark merge request as merged
Why
A customer wanted to use the API to mark an MR as merged because the change was already merged by and external tool.
What
PUT /projects/:id/merge_requests/:merge_request_id to accept state_event option mark_as_merged.
This could either be passed directly to the model or wrapped in a service to trigger any actions needed from PostMergeService. The model already has the following:
event :mark_as_merged do
transition [:reopened, :opened, :locked] => :merged
end