title: React Dropzone issue : children is not a function
body: <p>I've installed react dropzone in a react app. When adding the component dropzone, the app crashes, claiming that:</p>
  
  <pre><code>TypeError: children is not a function
  Dropzone.render
  node_modules/react-dropzone/dist/es/index.js:478
  475 | var isMultipleAllowed = multiple || filesCount &lt;= 1;
  476 | var isDragAccept = filesCount &gt; 0 &amp;&amp; 
  allFilesAccepted(draggedFiles, this.props.accept);
  477 | var isDragReject = filesCount &gt; 0 &amp;&amp; (!isDragAccept ||!isMultipleAllowed);
  &gt; 478 | return children({
    | ^  479 |   isDragActive: isDragActive,
  480 |   isDragAccept: isDragAccept,
  481 |   isDragReject: isDragReject,
  </code></pre>
  
  <p>Yet, everything seems fine. My App.js is:</p>
  
  <pre><code>import React, { Component } from 'react';
  import DropImg from './components/DropImg.js';
  
  class App extends Component {
  render() {
  return (
    &lt;div className="App"&gt;
     &lt;DropImg /&gt;
    &lt;/div&gt;
  )}}
  export default App;
  </code></pre>
  
  <p>and the component DropImg is:</p>
  
  <pre><code>import React, {Component} from "react";
  import Dropzone from "react-dropzone"
  
  class DropImg extends Component{
  render(){
      return(
          &lt;div&gt;
              &lt;h1&gt;Drop your file&lt;/h1&gt;
              &lt;Dropzone&gt;Drop file here&lt;/Dropzone&gt;
          &lt;/div&gt;
      )}}
  
  export default DropImg;
  </code></pre>
  
  <p>There are no functions to handle drag &amp; whatnot. Just a very basic set up. Yet it crashes. Why? The issue seems to come from the react-dropzone package itself.</p>
  
  <p>ps: I've read the documentation, but it was not crystal clear. It is the first time I'm implementing such a feature, could you please explain to me how to fix this issue in a simple manner? Thanks!</p>