Change merge request assigne

[zemzale]

Is your feature request related to a problem? Please describe.
In my organization we assigne one of the seniors/maintainers of the repo for them to review the MR when it's ready.
Right now I can create an merge request using this tool, but once the mr is in a state where it's ready to be merged I can't change the assignee to other maintainers to review them.

Describe the solution you'd like
Add another flag to mr update {id} command to change the assignee since that is the place where we already do all the change to existing merge requests.

Describe alternatives you've considered
We could add another command, but since we already got update I don't think we have to do that.

[zemzale]

As per GitLab API docs this should be trivial https://docs.gitlab.com/ee/api/merge_requests.html#update-mr

If there are no comments, or objections about it, I will start work on implementing this

[profclems]

Sounds a great idea @zemzale. You can go ahead. Thanks