title: Type 'Observable<boolean>' is not assignable to type 'Observable<BreakpointState>'
body: <p>Using angular-material schematic, I want to generate the navigation menu. For that I use the following command:</p>
  
  <pre><code>ng generate @angular/material:material-nav --name layout
  </code></pre>
  
  <p>When I serve my application, this error is thrown:</p>
  
  <blockquote>
    <p>error TS2322: Type 'Observable' is not assignable to type 'Observable'.
      Type 'boolean' is not assignable to type 'BreakpointState'.</p>
  </blockquote>