title: reading Git Build Data sha in pipeline
body: <p>What I am trying to accomplish is to implement re-try in the start of bitbucket jenkins multibranch pipeline PR job. Because the bitbucket plugin has no option for retry I want to do it in the pipeline code.</p>
  <p>My question is - How do I access following variable from pipeline: <strong>Git Build Data
  Revision: 71f7b48a53bf5e702f8b8d16f5fd2ca6c27decca</strong>. It is not visible if I print env, and it is not visible if I print parameters.</p>