title: how to downgrade angular-cli 1.7.3 to angular-cli 1.6.8
body: <p>I am getting issue in my Ubuntu regarding reinstalling of angular.
  my current version:
  Angular 1.7.3
  Node: 8.11.1
  OS: Linux
  Angular: 4.4.4</p>
  
  <p>I want to reinstall from angular 1.7.3 to angular 1.6.8</p>
  
  <p>Please help..</p>