title: How do you know what package version you need in angular?
body: <p>I had an asp.net core app on Angular 10.2.4, decided to upgrade to 11.
  Ran: <code>ng update @angular/core@11 @angular/cli@11</code> it failed complaining of devkit. Uninstalled devkit, upgraded angular to 11.2.14 OK.</p>
  <p>Now am trying to install devkit back.</p>
  <ul>
  <li><p><code>npm install @angular-devkit/build-angular --save-dev</code> - fail - seems try to install v12 and depends on cli 12 also.</p>
  </li>
  <li><p><code>npm install @angular-devkit/build-angular@11.2 --save-dev</code> or <code>npm install @angular-devkit/build-angular@11 --save-dev</code> - fail - No matching version found for @angular-devkit/build-angular@xx</p>
  </li>
  </ul>
  <p>What's the right version of devkit for Angular 11? What's the general idea on how to find/infer/guess correct version of a package for a certain Angular version?</p>