title: readme-md-generator not updating version from package JSON
body: <p>Is it possible to have my readme auto update the version of my self published package when I update the package JSON? </p>
  
  <p>Right now the readme (created with <code>readme-md-generator</code>) does not the relevant section looks like this:
  //readme.md</p>
  
  <pre><code>&lt;h1 align="center"&gt;Welcome to bla bla &lt;/h1&gt;
  &lt;p&gt;
    &lt;img src="https://img.shields.io/badge/version-1.1.7-blue.svg?cacheSeconds=2592000" /&gt;
  &lt;/p&gt;
  </code></pre>
  
  <p>Whereas in my package JSON it has:</p>
  
  <pre><code>{
    "name": "bla bla",
    "version": "1.1.13",
  ...
  }
  </code></pre>
  
  <p>I tried importing the package JSON but that did not work as it displayed as HTML. How can I get this to update? (without manually typing it in each time)</p>