title: how to trigger a downstream pipeline on a tagged branch in gitlab multi project pipeline?
body: <p>I would like to trigger a GitLab project, but instead of using a branch, I would like to use a specific tag. How can this be achieved?</p>
  <p>The following triggers the <code>develop</code> branch of <code>some-project</code>:</p>
  <pre><code>bridge:
    stage: bridge
    trigger:
      project: some-project
      branch: develop
  </code></pre>