We need a GitLab validator.
The default Gerrit validator requires that a Change-Id be present. This is also where most of the Wikimedia commit message rules are currently implemented. The new GitLab validator should implement all of the rules from the Gerrit validator except requiring Change-Id to be present. It probably should allow Change-Id however so that folks can still use https://github.com/yaoyuannnn/gerritlab in their projects if they really want to.