title: Why should version numbers not be pinned in a Pipfile?
body: <p>I'm looking into using pipenv and in the docs here<br />
  <a href="https://pipenv.pypa.io/en/latest/basics/#importing-from-requirements-txt" rel="noreferrer">https://pipenv.pypa.io/en/latest/basics/#importing-from-requirements-txt</a></p>
  <p>it says (emphasis mine)</p>
  <blockquote>
  <p>Note, that when importing a requirements file, they often have version
  numbers pinned, which you likely <strong>won’t want</strong></p>
  </blockquote>
  <p>Why is this?</p>
  <p>I understand that the Pipfile.lock file will store the specific versions and hashes of the dependencies I install but don't I want to be able to see the specific versions of what is installed in Pipfile? (The same way I do when I use a requirements.txt?)</p>