title: React Native TextInput: placeholder and detx padding
body: <p>I have a TextInput with rounded corners :</p>
  
  <pre><code>&lt;TextInput
      style={{
          backgroundColor : '#FFFFFF',
          borderRadius : 30,
          marginLeft : 8,
          marginRight : 8,
          marginTop : 10
      }}
      placeholder = 'A placeholder'
  /&gt;
  </code></pre>
  
  <p>but i would like to give some left padding to placeholder (and text that will be contained inside TextInput), because now text is too near to left TextInput border.
  How can i do it?</p>