fix: react.createElement type is invalid (#42)

Author: Aidurber

js/PickerAndroid.ios.js

@@ -12,4 +12,4 @@
 import React from 'react';
 import {UnimplementedView} from 'react-native';
 
-export default <UnimplementedView />;
+export default UnimplementedView;

js/PickerIOS.android.js

@@ -16,4 +16,4 @@
 import React from 'react';
 import {UnimplementedView} from 'react-native';
 
-export default <UnimplementedView />;
+export default UnimplementedView;