Cleanup library and port CI to GitHub Actions

[mhostetter]

Attempt two, as motivated by #4...

[codecov-commenter]

Codecov Report

Merging #6 (0d5e800) into master (8ab4150) will decrease coverage by 0.76%.
The diff coverage is 29.78%.

@@            Coverage Diff             @@
##           master       #6      +/-   ##
==========================================
- Coverage   87.40%   86.64%   -0.77%     
==========================================
  Files          22       23       +1     
  Lines         786      801      +15     
==========================================
+ Hits          687      694       +7     
- Misses         99      107       +8     

Impacted Files	Coverage Δ
nhl/conference.py	94.44% <0.00%> (ø)
nhl/division.py	94.44% <0.00%> (ø)
nhl/event.py	63.93% <0.00%> (-5.71%)	⬇️
nhl/franchise.py	93.75% <0.00%> (ø)
nhl/game.py	83.87% <0.00%> (ø)
nhl/gameinfo.py	58.06% <0.00%> (-1.94%)	⬇️
nhl/gametime.py	77.41% <0.00%> (-2.59%)	⬇️
nhl/location.py	84.21% <0.00%> (ø)
nhl/official.py	80.00% <0.00%> (ø)
nhl/statsapi/parse.py	97.14% <ø> (ø)
... and 5 more

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