title: Unknown option: '--service-worker' creating new angular pwa
body: <p>I'm trying to create a new angular PWA, but when I execute<code>ng new pwa --service-worker</code> the system returns <strong>Unknown option: '--service-worker'</strong></p>
  
  <p>Any idea what's wrong?</p>
  
  <ul>
  <li>OS: ubuntu gnome 16.04</li>
  <li>Node: v10.16.0</li>
  <li>Npm: 6.9.0</li>
  </ul>