get version info from module

[podhmo]

from #98

Also would you consider exposing version in module's root ? It is quite common to be able to do this:

from swagger_marshmallow_codegen import __version__

print(__version__)
# Shows "0.6.3")

[podhmo]

• https://stackoverflow.com/questions/58202909/modulenotfounderror-when-using-setup-cfg-and-version-accessed-with-attr
• https://setuptools.readthedocs.io/en/latest/history.html#id141