title: Upgrade the Python package dateutil: Could not find a version
body: <p>I tried to upgrade <code>dateutil</code> from <code>2.5.3</code> to the newest version <code>2.6.0</code> with <code>pip install dateutil --upgrade</code>, but got the issue <code>Could not find a version</code>.</p>
  
  <pre><code>$ pip install dateutil --upgrade
  Collecting dateutil
    Could not find a version that satisfies the requirement dateutil (from versions: )
  No matching distribution found for dateutil
  </code></pre>
  
  <p>I checked the post <a href="https://stackoverflow.com/questions/32302379/could-not-find-a-version-that-satisfies-the-requirement-package">Could not find a version that satisfies the requirement </a>. Running <code>pip freeze | grep dateutil</code> got,</p>
  
  <pre><code>$ pip freeze | grep dateutil
  python-dateutil==2.5.3
  </code></pre>
  
  <p>How do I know which version satisfies my machine? Is it possible to upgrade <code>dateutil</code> to the newest version?</p>