Migrate Travis to GitHub Actions

[alexdlaird]

No description provided.

[codecov]

Codecov Report

Merging #78 (bbb0d53) into master (26e7e50) will decrease coverage by 2.67%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #78      +/-   ##
==========================================
- Coverage   93.79%   91.11%   -2.68%     
==========================================
  Files           5        5              
  Lines         564      563       -1     
==========================================
- Hits          529      513      -16     
- Misses         35       50      +15     

Impacted Files	Coverage Δ
pyngrok/ngrok.py	86.04% <100.00%> (-4.66%)	⬇️
pyngrok/process.py	90.33% <0.00%> (-2.90%)	⬇️
pyngrok/installer.py	95.31% <0.00%> (-0.82%)	⬇️

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