Add generate-jitconfig API for self-hosted runners

[mkulke]

GitHub recently introduced just-in-time configuration for self-hosted runner, so runners do not need to be seeded with privileged tokens. This PR adds those endpoints for orgs + repos.

[gmlewis]

Thank you, @mkulke.

[gmlewis]

Please remember to run go generate ./... at the top-level of the repo and push (not force-push) the changes to this PR.
See CONTRIBUTING.md for more details.

[gabriel-samfira]

Hi @mkulke !

I know the docs don't mention enterprises (although the blog seems to). I would be surprised if this was missing for enterprises/%v/actions/runners/generate-jitconfig.

I think I can ask someone to test this out. But I think that can be added as a separate PR. I don't want to block this one 😄.

[mkulke]

Hi @mkulke !

I know the docs don't mention enterprises (although the blog seems to). I would be surprised if this was missing for enterprises/%v/actions/runners/generate-jitconfig.

I think I can ask someone to test this out. But I think that can be added as a separate PR. I don't want to block this one 😄.

yeah, I was also wondering about that and opted to limit it to what's documented atm.

[gabriel-samfira]

yeah, I was also wondering about that and opted to limit it to what's documented atm.

Thanks for adding this!

[gmlewis]

Thank you, @mkulke !
LGTM.

Awaiting second LGTM+Approval from any other contributor to this repo before merging.

[codecov]

Codecov Report

Merging #2801 (82526e3) into master (3efdd2c) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #2801   +/-   ##
=======================================
  Coverage   98.06%   98.06%           
=======================================
  Files         132      132           
  Lines       11650    11676   +26     
=======================================
+ Hits        11424    11450   +26     
  Misses        154      154           
  Partials       72       72           

Impacted Files	Coverage Δ
github/messages.go	100.00% <ø> (ø)
github/actions_runners.go	100.00% <100.00%> (ø)
github/event.go	100.00% <100.00%> (ø)

[valbeat]

LGTM!

[gmlewis]

Thank you, @valbeat !
Merging.