Add support for dashes and underscores in Python version numbers

[nickiemc]

Non-normalized Python versions can include dashes (-) and underscores (_) in place of periods (.).

PythonVersionInfo should be updated to allow these characters.

[nickiemc]

Relevant error messages from https://github.com/explosion/spaCy:

Error adding version to regex release history: Unable to parse version string:   '2013-02-16'.
Error adding version to regex release history: Unable to parse version string: '2013-02-23'.
Error adding version to regex release history: Unable to parse version string: '2013-03-11'.
Error adding version to regex release history: Unable to parse version string: '2013-05-21'.
Error adding version to regex release history: Unable to parse version string: '2013-06-05'.
Error adding version to regex release history: Unable to parse version string: '2013-06-26'.
Error adding version to regex release history: Unable to parse version string: '2013-08-04'.
Error adding version to regex release history: Unable to parse version string: '2013-10-04'.
Error adding version to regex release history: Unable to parse version string: '2013-10-12'.
Error adding version to regex release history: Unable to parse version string: '2013-10-21'.
Error adding version to regex release history: Unable to parse version string: '2013-10-22'.
Error adding version to regex release history: Unable to parse version string: '2013-10-23'.
Error adding version to regex release history: Unable to parse version string: '2013-10-24'.
Error adding version to regex release history: Unable to parse version string: '2013-10-25'.
Error adding version to regex release history: Unable to parse version string: '2013-10-26'.
Error adding version to regex release history: Unable to parse version string: '2013-11-29'.
Error adding version to regex release history: Unable to parse version string: '2013-12-31'.

Note: This is not actually causing an analysis error in the spaCy as none of these versions are used by spaCy.