ci: Update GH API

[pawelpasterz]

Fixes #1377

This PR adds new requests for flank's GH client. Currently not used. Commit was cherry-picked to make future PR (related to flank scripts/IT) smaller

Test Plan

How do we know the code works?

N/A

[github-actions]

Timestamp: 2020-12-08 13:38:02
Buildscan url for ubuntu-workflow run 408321670
https://gradle.com/s/gn2a3cpzxr3qs

[Sloox]

I want to confirm if the kotlinx serialization is fully compatible with the GSON we are making use of
Else if might result in us changing all the annotations.

[pawelpasterz]

I think they are, not 100% sure though. In flank-scripts module we do not use GSON.

[Sloox]

I saw here we are DE serializing with GSON so just want to confirm.

[piotradamczyk5]

Wait what? We should not do that

[pawelpasterz]

@Sloox could you give an example? I am unable to find

[codecov-io]

Codecov Report

Merging #1378 (b4d5e22) into master (5081a69) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master    #1378      +/-   ##
============================================
- Coverage     77.84%   77.82%   -0.03%     
  Complexity      706      706              
============================================
  Files           245      245              
  Lines          4713     4713              
  Branches        904      904              
============================================
- Hits           3669     3668       -1     
  Misses          551      551              
- Partials        493      494       +1     

[Sloox]

Had a look for the Serialization compatibility. It appears to be fine as far as I am aware.