title: python `deactivate` command can't exit virtualenv
body: <p>I'm on macOS Catalina [10.15]. Here is what I get when try to deactivate:</p>
  
  <pre><code>(django-learning) ~/git/stats-k8s/k8s-monitor (master) $ deactivate
  DeprecationWarning: 'source deactivate' is deprecated. Use 'conda deactivate'.
  (django-learning) ~/git/stats-k8s/k8s-monitor (master) $
  (django-learning) ~/git/stats-k8s/k8s-monitor (master) $
  (django-learning) ~/git/stats-k8s/k8s-monitor (master) $
  (django-learning) ~/git/stats-k8s/k8s-monitor (master) $ conda deactivate
  
  CommandNotFoundError: Your shell has not been properly configured to use 'conda deactivate'.
  To initialize your shell, run
  ...    
  IMPORTANT: You may need to close and restart your shell after running 'conda init'.
  (django-learning) ~/git/stats-k8s/k8s-monitor (master) $
  </code></pre>
  
  <p>I already looked at question: <a href="https://stackoverflow.com/questions/990754/how-to-leave-exit-deactivate-a-python-virtualenv">How to leave/exit/deactivate a Python virtualenv</a> but did not help.</p>