Update to Standard React Native Template import

react-native default template uses import React from 'react' and this is now supported the the allowSyntheticDefaultImports enabled.

App.tsx

@@ -6,7 +6,7 @@
  * https://github.com/emin93/react-native-template-typescript
  */
 
-import * as React from 'react';
+import React from 'react';
 import {
   Platform,
   StyleSheet,

__tests__/App.tsx

@@ -1,5 +1,5 @@
 import 'react-native';
-import * as React from 'react';
+import React from 'react';
 import App from '../App';
 
 // Note: test renderer must be required after react-native.