remove tsx extension

Author: Mitchel Severe

src/index.js

@@ -2,7 +2,7 @@ import 'babel-polyfill';
 import React from 'react';
 import ReactDOM from 'react-dom';
 import { Provider } from 'react-redux';
-import App from './App.tsx';
+import App from './App';
 import store from './store';
 
 ReactDOM.render(