title: How to check if git tag exist via jenkins
body: <p>I am new to Jenkins,
  In the CI build I would like to check if a specific TAG exist on my git branch</p>
  
  <p>I am trying to use the following plugin</p>
  
  <p><a href="https://wiki.jenkins-ci.org/display/JENKINS/Git+Client+Plugin" rel="nofollow">https://wiki.jenkins-ci.org/display/JENKINS/Git+Client+Plugin</a></p>
  
  <p>But I am not sure how to operate it</p>