title: scrollToEnd in Angular 8 didn't emit an event
body: <p>I'm trying to handle an event reaching end of scroll in select component, and, it seems, the event is not even emitted.</p>
  
  <p>But at the same time, similar events like 'open' work fine.</p>
  
  <p>I use Angular 8 in my project.</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;ng-select
    ...
    (open)="onOpen()"
    (scrollToEnd)="onScrollToEnd($event)"&gt;
  &lt;/ng-select&gt;
  </code></pre>
  
  <pre class="lang-js prettyprint-override"><code>onOpen() {
    console.log('open');
  }
  onScrollToEnd(e) {
    console.log('scroll to end');
  }
  </code></pre>
  
  <p>What could be the problem?</p>