title: How to differentiate build triggers in Jenkins Pipeline
body: <p>I'm hoping to add a conditional stage to my Jenkinsfile that runs depending on how the build was triggered. Currently we are set up such that builds are either triggered by: </p>
  
  <ol>
  <li>changes to our git repo that are picked up on branch indexing </li>
  <li>a user manually triggering the build using the 'build now' button in the UI. </li>
  </ol>
  
  <p>Is there any way to run different pipeline steps depending on which of these actions triggered the build?</p>