title: Getting a branch name I work on with GitHub Webhook on Pull Requests
body: <p>I am trying to get all the details from a WebHook trigger when labelling a Pull Request on Git Hub. 
  I am getting a lot of info with the payload but the one thing I really need is the Branch name I work on that has the Pull Request I opened.</p>
  
  <p>In GitHub page I see:
  Pavel wants to merge 2 commits into master from  &lt;-- I'd like to obtain that branch name somehow..
  Thanks!</p>