[ANNOUNCE] Weston now uses GitLab for review

[Daniel Stone]

Hi all,
Weston is now using GitLab merge requests for patch submission and
review, rather than the mailing list and Patchwork. \o/

The contribution guide covers how to create a merge request and the
review process in general:
https://gitlab.freedesktop.org/wayland/weston/blob/master/CONTRIBUTING.md

If you spot something that's missing in there, or if anything is
confusing and should be clarified, please either follow up here or,
well, send a merge request to improve the document. Making
contributors' lives easier is definitely a good thing.

The existing backlog of patches in Patchwork will _not_ be
automatically converted to MRs. We should try to drain our review
queue and then make a series-by-series decision on what to do with the
older patches, until we have no Weston patches left in Patchwork. I'm
sure many submitters would prefer to resubmit themselves, but on the
other hand, some submitters will have vanished in the intervening
years.

Thanks everyone who's worked and provided a lot of feedback over the
years to help make this happen.

Cheers,
Daniel