title: Gitlab-CI Environment Variable for Commit Comment
body: <p>I'm currently using GitLab-CI to CD my project's staging branch to Google Firebase.
  Each deployment gets a special comment with the PipelineID and Build ID.</p>
  
  <pre><code>firebase deploy -m "Pipeline $CI_PIPELINE_ID, build $CI_BUILD_ID" --non-interactive --token $FIREBASE_DEPLOY_KEY
  </code></pre>
  
  <p>For ease of use, when rolling back commits in the Firebase console, I'd like to include the commit message into the deploy comment. </p>
  
  <p>I searched through the documentation and didn't find a variable for that. Am I mistaken, or is that really not possible?</p>
  
  <p>Thanks for your help!</p>