title: npm install from github pull request
body: <p>Loooking at the <a href="https://docs.npmjs.com/cli/install">npm install docs</a> it looks possible to npm install from a github repo.  </p>
  
  <p>Is it also possible to install specifically from a pull request?</p>
  
  <p>Is the solution just to install based on the last commit (last sha) of the pull request? </p>