title: Ionic 4: ionic-select is not selected if the model is a number
body: <p>I have the following code snippet for html and javascript. Notice that the <code>id</code> is of type <code>number</code>. When the page is loaded, the first option is not selected even if the <code>model</code> has the value for the first option.</p>
  
  <p>Note. It works fine if I make the <code>id</code> field a <code>string</code>.</p>
  
  <p>/** HTML snippet **/</p>
  
  <pre><code> &lt;ion-item&gt;
       &lt;ion-label&gt;Select Color&lt;/ion-label&gt;
       &lt;ion-select [(ngModel)]="selectedId" placeholder="Select"&gt;
  
           &lt;ion-select-option *ngFor="let color of colors" [value]="color.id"&gt;
               {{color.label}}
           &lt;/ion-select-option&gt;
       &lt;/ion-select&gt;
   &lt;/ion-item&gt;
  </code></pre>
  
  <p>/** Typescript snippet **/</p>
  
  <pre><code> colors = [
       {id: 1, label: 'Red'},
       {id: 2, label: 'Yellow'},
       {id: 3, label: 'Green'}
   ]
  
   selectedId = colors[0].id;
  </code></pre>