title: how to get target branch from a pull request using azure devops api or other methods?
body: <p>I'm trying to make a single build pipeline for 3 env (dev, qa, prod) but with ability to choose which one to build from.</p>
  <p>The idea is to keep the pipeline on prod branch or another repo, and not having it in every env.
  The issue now is that on a PR it will start the pipeline only on master(prod) branch as it shall contain the yml file.</p>
  <p>Is there a way to get the PR target branch in order to add additional conditions for PR triggers?</p>