title: Change the default React Native <Picker> drop-down arrow icon
body: <p>I want to change its color specifically:</p>
  
  <pre><code>&lt;Picker selectedValue={this.state.selected}
          onValueChange={(value) =&gt; this.setState({selected:value})}  &gt;
    {data.map ((value)=&gt;&lt;Picker.Item label={value} value={value} key={value}/&gt;)}
  &lt;/Picker&gt;
  </code></pre>