Update accessibility to use cross platform props accessibilityRole (#80)

* Update accessibility to use cross platform props accessibilityRole

* Update Button.js

Author: enrique-money

Button.js

@@ -50,8 +50,7 @@ export default class Button extends Component {
         testID={this.props.testID}
         style={containerStyle}
         accessibilityLabel={this.props.accessibilityLabel}
-        accessibilityTraits="button"
-        accessibilityComponentType="button">
+        accessibilityRole="button">
         {this._renderGroupedChildren()}
       </TouchableOpacity>
     );