title: GitHub Branch name from which the Pull Request is raised
body: <p>I'm using Multibranch Pipeline Job in Jenkins.</p>
  
  <p>How do I find the branch name from which the Pull Request is raised in GitHub?</p>
  
  <p>I'm using <code>/github-webhook/</code> &amp; also tried with <code>/ghprbhook/</code> and tried with the following environment variables: <code>GIT_LOCAL_BRANCH</code>, <code>GIT_BRANCH</code>, <code>ghprbSourceBranch</code>, but I didn't get any result.</p>
  
  <p>If there are any suggestions, I would love to try them.</p>