title: Trigger GitHub action on merge of Pull Request with specific tag
body: <p>I am trying to use GitHub actions to automatically create a release when a Pull Request with the tag <code>Update</code> is merged.</p>
  
  <p>At the moment, my workflow triggers when a Pull Request is merged, but I am not sure how to make the workflow only continue if the Pull Request has the <code>Update</code> tag.</p>
  
  <p><strong>Current Workflow</strong></p>
  
  <pre class="lang-yaml prettyprint-override"><code>name: Create Release
  
  on:
    pull_request:
      types: [closed]
  
  jobs:
    release:
      if: github.event.pull_request.merged == true
  
      ...rest of workflow...
  
  </code></pre>