title: cant install yarn package from github
body: <p>I'm trying to install a package from GitHub with <code>yarn</code>.</p>
  
  <p>I have done this thing a lot before, but I'm not success with this repo:</p>
  
  <p><code>https://github.com/coolwanglu/pdf2htmlEX</code></p>
  
  <p>I already tried without luck:<br></p>
  
  <pre><code>yarn add git+https://github.com/coolwanglu/pdf2htmlEX
  yarn add git+https://github.com/coolwanglu/pdf2htmlEX.git
  yarn add https://github.com/coolwanglu/pdf2htmlEX
  yarn add https://github.com/coolwanglu/pdf2htmlEX.git
  yarn add https://coolwanglu@github.com/pdf2htmlEX
  yarn add https://coolwanglu@github.com/pdf2htmlEX.git
  </code></pre>