chore: migrate example to TS

packages/stack/example/src/FullScreen.tsx

@@ -0,0 +1,15 @@
+import * as React from 'react';
+import { View } from 'react-native';
+import { createStackNavigator } from 'react-navigation-stack';
+
+class Screen extends React.Component {
+  static navigationOptions = {
+    header: null,
+  };
+
+  render() {
+    return <View style={{ flex: 1, backgroundColor: 'red' }} />;
+  }
+}
+
+export default createStackNavigator({ Screen });