title: Azure Branch PR Policy - Require Source Branch Be Up-To-Date
body: <p>I'm trying to get quality branch policies on my <code>develop</code> branch and so far I've got some good basics:</p>
  
  <ul>
  <li>requiring reviewers to approve</li>
  <li>requiring all checks to pass</li>
  <li>limiting merge types</li>
  </ul>
  
  <p>What I want to ensure is that a source branch in a PR must be up-to-date with its target branch. I cannot seem to find this setting and was wondering if anyone knew if it existed.</p>
  
  <p>GitHub has this as an available PR restriction:</p>
  
  <p><a href="https://i.stack.imgur.com/DyIab.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/DyIab.png" alt="GitHub sample"></a></p>