PEP compliant `__version__` for python

[AreWeDreaming]

Affiliation
General Atomics
Description
The current cmake build process yields PEP incompliant __version__ strings that are separated by dashes instead of dots. This is not great for the conda-forge releases of MDSplus we maintain at GA . I was hoping by just setting
-DRELEASE_TAG=7.157.0 to a proper version string I could trick the cmake process but that just crashes. For now I will manually hack the __version__ after the cmake build is complete but that is not a great forever solution.

[AreWeDreaming]

I managed to finally hack my way around things for the conda-forge build but then I now get this in the built MDSPlus release on import

Warning:
  The MDSplus python module version (7.157.0) does not match
  the version of the installed MDSplus libraries (alpha_release-7-157-0).
  Upgrade the module using the mdsplus/python/MDSplus directory of the
  MDSplus installation or set PYTHONPATH=/usr/local/mdsplus/python.

[mwinkel-dev]

https://packaging.python.org/en/latest/specifications/version-specifiers/#version-specifiers

[mwinkel-dev]

This issue might also apply to the mdsthin program.