title: How to include Source Branch name or pull request ID in ADO release title?
body: <p>I have a CD release pipeline which gets deployed whenever new Pull Request (PR) build is succeeded. I want to include the source branch name of that PR as well as PR id in my release title.</p>
  <p>I tried below variables in title, but they didn't work:</p>
  <p>$(system.pullRequest.sourceBranch)</p>
  <p>$(BUILD.PullRequest.SourceBranch)</p>
  <p>$(BUILD.PullRequest.ID)</p>
  <p>I just don't want to use $(Build.SourceBranch) or $(Build.SourceBranchName) as it doesn't give me expected value.</p>
  <p>My expected release title:
  &quot;PR Run- personal/ak/randombuild with PRID 1234 - 01&quot;</p>