`packaging.version` fails to parse legit PyPI package version

[keshav-space]

packaging.version is unable to parse some PyPI package version.

Here’s an example for https://pypi.org/project/nltk/2.0.1rc2-git/, where packaging fails to parse the nltk version 2.0.1rc2-git:

>>> from packaging.version import Version
>>> Version("2.0.1rc2-git")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/../venv/lib/python3.10/site-packages/packaging/version.py", line 202, in __init__
    raise InvalidVersion(f"Invalid version: {version!r}")
packaging.version.InvalidVersion: Invalid version: '2.0.1rc2-git'

In light of this we should reconsider how we handle PyPI package versions in Univers. We can not rely on packaging.version for these cases.