title: Problem installing monogame.extended package
body: <p>I am having a problem installing monogame extended while running
   <code>Install-Package MonoGame.Extended</code>
  at nuget console.
  I get this error :</p>
  
  <pre><code>unable to find package "Monogame.Extended"
  </code></pre>
  
  <p>I am using visual studio community 2017,
  I have already opened a new monogame project.</p>