feat(github): Add checkrun support

[davhdavh]

• Cleans up the github code so that each new template-supported prop only takes a single line (instead of 10+)
• Add support for CheckRuns
• Add a bit of documentation for all of the supported APIs

[davhdavh]

That linter is really annoying, could it not just give ALL of the errors in 1 run, instead of taking 8...

anyway, how to solve the last one?

  Error: composites: github.com/google/go-github/v41/github.Timestamp struct literal uses unkeyed fields (govet)

[codecov]

Codecov Report

Attention: 74 lines in your changes are missing coverage. Please review.

Comparison is base (a8d185e) 55.13% compared to head (ae1870f) 54.74%.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #223      +/-   ##
==========================================
- Coverage   55.13%   54.74%   -0.40%     
==========================================
  Files          35       35              
  Lines        3337     3352      +15     
==========================================
- Hits         1840     1835       -5     
- Misses       1230     1263      +33     
+ Partials      267      254      -13     

Files	Coverage Δ
pkg/services/github.go	32.05% <39.34%> (-3.61%)	⬇️

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[davhdavh]

There is no existing tests for the api calls, so I have no idea how to make test for the new api call.