title: GitHub Branch Source Plugin --> only scan for Pull Requests
body: <p>We use the <a href="https://wiki.jenkins.io/display/JENKINS/GitHub+Branch+Source+Plugin" rel="nofollow noreferrer">GitHub Branch Source Plugin</a> in Jenkins. It works great. However it scans both for branches and pull requests. </p>
  
  <p>We want to configure the plugin in such way that it only scans for pull requests. Is this possible? If not, where can we post our feature request?</p>