title: Jenkins multibranch pipeline does not detect pull requests in Bitbucket server
body: <p>I am having trouble getting Jenkins multibranch pipeline detect pull requests created in the Bitbucket server (private instance). I have setup the "Bitbucket server webhook to Jenkins" which is triggering the build on master, develop and feature branches except pull-requests. I have defined the build steps in Jenkisfile and can confirm the PR branch also includes the Jenkinsfile.
  In the Jenkins configuration, I have enabled "Discover branches" under Branch Sources configuration</p>