Add detailed logging on publish

[timja]

Hopefully will help with:

I'm also hitting it in production, a lot of checks aren't getting published, but logs all seem fine

[codecov]

Codecov Report

Merging #68 into master will increase coverage by 0.35%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##             master      #68      +/-   ##
============================================
+ Coverage     79.30%   79.65%   +0.35%     
  Complexity      106      106              
============================================
  Files             8        8              
  Lines           343      349       +6     
  Branches         36       36              
============================================
+ Hits            272      278       +6     
  Misses           50       50              
  Partials         21       21              

Impacted Files	Coverage Δ	Complexity Δ
...s/plugins/checks/github/GitHubChecksPublisher.java	97.36% <100.00%> (+0.49%)	5.00 <2.00> (ø)

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