Andrea Veri commented:
@mjog, if you're proposing to shut the mirror down I believe you'd have to reach out to the community as a whole and get a consensus.
What I can do from my side is eventually looking into whether we can copy a merge request over to GitLab before actually closing it and provide the URL to the copied MR to the github user. That in addition to #79 (to make sure we don't receive MRs against projects that are not maintained anymore) are definitely going to help to avoid contributors' frustration.