title: How to refresh the job configuration from pipeline in SCM
body: <p>If I add a new job parameter to a pipeline script held in SCM, how do I then make the the UI update with the new param? (without running and having the job fail because the pipeline hasn't yet been pulled from SCM)</p>
  
  <p>To go into more detail, I add a new param to the pipeline script in SCM like so: </p>
  
  <pre><code>choice(
      choices: ['github', 'bitbucket'],
      description: 'Which repo to build from',
      name: 'repo')
  </code></pre>
  
  <p>And then click the job - > ' build with parameters' in the UI. The exsiting selection of parameters doesnt contain the new one because Jenkins hasnt yet retrieved it from SCM. If I were to run now it would fail (but also at the same time it updates the list of params, so next time I 'Build with parameters' it will be there.</p>