title: Cropped icon with native base button
body: <p>I'm using native base to create round icon buttons.<br>
  When the icon is small it works fine : </p>
  
  <pre><code>&lt;Button   
      rounded 
      style={{
          borderRadius : 32,
          width : 64,
          height : 64,
  
      }} 
  &gt;
      &lt;Icon  
          name="bell"
          type="MaterialCommunityIcons"
          style={{
              fontSize: 35, 
              marginLeft : 14
          }}
      /&gt;
  &lt;/Button&gt;
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/uUvv8.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/uUvv8.png" alt="Icon works fine"></a><br>
  When I change the icon size, it becomes cropped</p>
  
  <pre><code>&lt;Button   
      rounded 
      style={{
          borderRadius : 32,
          width : 64,
          height : 64,
  
      }} 
  &gt;
      &lt;Icon  
          name="bell"
          type="MaterialCommunityIcons"
          style={{
              fontSize: 60, //bigger icon
              marginLeft : 3
          }}
      /&gt;
  &lt;/Button&gt;
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/UEXC0.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/UEXC0.png" alt="Icon is cropped"></a><br>
  What should I do to display the icon over the button?<br>
  EDIT : 
  The problem gets worse as the button becomes smaller (the vertical cropping line gets closer to the button's center)   </p>