title: Python: How can I update python version in pyenv-virtual-environment?
body: <p>I used <code>pyenv</code>, <code>pyenv-virtualenv</code> for managing python virtual environment.</p>
  
  <p>I have a project working in <code>Python 3.4</code> virtual environment.</p>
  
  <p>So all installed packages(<code>pandas</code>, <code>numpy</code> etc) are not newest version.</p>
  
  <p>What I want to do is to upgrade <code>Python</code> version from 3.4 to 3.6 as well as upgrade other package version to higher one.</p>
  
  <p>How can I do this easily?</p>