ProjectRemoteMirrors is missing `sync`

Description

Support for "Force push mirror update" is missing - https://docs.gitlab.com/ee/api/remote_mirrors.html#force-push-mirror-update

Proposal

I hotfixed the NPM module as follows, adding sync() to ProjectRemoteMirrors:

  sync(projectId, mirrorId) {
    return RequestHelper.post()(
      this,
      endpoint`projects/${projectId}/remote_mirrors/${mirrorId}/sync`
    );
  }

This seems to work

Checklist

[x] I have checked that this is not a duplicate issue.
[x] I have read the documentation.

jdalrymple / gitbeaker

ProjectRemoteMirrors is missing `sync` #3616