Setup for publishing on PyPI

[rlskoeser]

ref #21

in this PR:

• add python publish workflow (using default provided by GitHub)
• update readme and setup files for publishing
• tested publishing on test pypi and tuned
• manually published a pre release version to check everything and so I could create a pypi api token with project-specific scope
• added a repository secret with new api token

[codecov[bot]]

Codecov Report

Merging #60 (9554bc9) into main (987ab7f) will increase coverage by 0.33%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #60      +/-   ##
==========================================
+ Coverage   97.41%   97.74%   +0.33%     
==========================================
  Files           4        4              
  Lines         116      133      +17     
==========================================
+ Hits          113      130      +17     
  Misses          3        3              

Impacted Files	Coverage Δ
tests/test_dateformat/test_base.py	100.00% <100.00%> (ø)
tests/test_undate.py	100.00% <100.00%> (ø)

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[rlskoeser]

All of the tox config is now part of setup.cfg?

yeah, that was added at some point in the last round of development, maybe shortly after the hackathon