title: Branch Policy: Require atleast 1 Approval from specified approvers
body: <p>We have 6 people on the project team: 1 Tech-lead and 1 Assistant Tech-lead.</p>
  <p>In our branch policy we want to require that only the Tech-lead or Assistant Tech-lead can approve the pull request. We only need approval from one of them to avoid a bottleneck if the other one is on leave.</p>
  <p>The problem is there are only 2 choices in the branch policy settings:</p>
  <ol>
  <li>Specifying the number of required approvers (which will not work since normal developers would be able to approve as well)</li>
  <li>Specifying the actual person to approve (which will not work since both of them will be required and cause a bottleneck when one is on leave)</li>
  </ol>
  <p>Can someone please point us in the right direction?</p>