title: Change navigation header background color
body: <p>Struggling to understand how to change the navigation header bar background color.
  I'm Using react navigation and Expo to build my app.</p>
  
  <p><code>backgroundColor</code> does not seem to do anything. Any idea how to do this?</p>
  
  <p>My code is below:</p>
  
  <pre><code>static navigationOptions = () =&gt; ({
      title: 'My App',
      headerTintColor: Colors.DarkBlue,
      backgroundColor: 'red',
      headerLeft:
        &lt;HeaderBarItem to='InfoScreen' title='App info' /&gt;,
      headerRight:
        &lt;HeaderBarItem to='FeedbackScreen' title='Feedback' /&gt;
    });
  </code></pre>