title: How to fix React 15.5.3 PropTypes deprecated warning when using create-react-app
body: <p>I'm using <a href="https://github.com/facebookincubator/create-react-app" rel="noreferrer">create-react-app</a> to start <code>React</code> project.
  At latest <code>React 15.5.3</code> package, it appears following warnings:</p>
  
  <blockquote>
    <p>Warning: Accessing PropTypes via the main React package is deprecated.
    Use the prop-types package from npm instead.</p>
  </blockquote>
  
  <p>I have already follow the <a href="https://facebook.github.io/react/blog/2017/04/07/react-v15.5.0.html" rel="noreferrer">blog</a>:</p>
  
  <p><code>npm install prop-types</code> and <code>import PropTypes from 'prop-types';</code></p>
  
  <p>but it doesn't work.
  I don't use any <code>PropTypes</code> or <code>props</code> in code:</p>
  
  <pre><code>import React, { Component } from 'react';
  import PropTypes from 'prop-types';
  
  class App extends Component {
      constructor() {
          super();
          this.state = {
              videoVisible: true,
          };
      }
  
      ......
  }
  </code></pre>
  
  <p>How to fix that?</p>
  
  <p>Thanks.</p>