Add support for new actions APIs

[stevehipwell]

GitHub announced new actions REST APIs for the following purposes at the repository, organization and enterprise level.

• Approval for running fork pull request workflows from contributors
• Allowing workflows on fork pull requests in private repositories
• Setting which repositories can create repository-level self-hosted runners
• Setting artifact and log retention periods

[gmlewis]

This would be a great PR for any new contributor to this repo or a new Go developer.
All contributions are greatly appreciated!

Feel free to volunteer for any issue and the issue can be assigned to you so that others don't attempt to duplicate the work.
Also feel free to perform a code review on any PR that has the label "NeedsReview" - we appreciate those contributions too!
We have a REVIEWERS file that you could add your username to if you are willing to be contacted when reviews are needed.

Please check out our CONTRIBUTING.md guide to get started. (In particular, please remember to go generate ./... and don't use force-push to your PRs.)

Thank you!

[zyfy29]

Hello! I'm new to this project and I'd like to contribute to this issue.

[gmlewis]

Hello! I'm new to this project and I'd like to contribute to this issue.

Thank you, @zyfy29 - but first I need to ask @stevehipwell - were you planning on working on this since you just updated OpenAPI in #3662, or may I go ahead and assign this issue to @zyfy29 ?

[stevehipwell]

@zyfy29 you're more than welcome to pick this up. Thank you.

[zyfy29]

@stevehipwell @gmlewis I will try my best, thank you!

[gmlewis]

@stevehipwell @gmlewis I will try my best, thank you!

Excellent, @zyfy29, thank you! It's yours.

[AlanCitrix]

Getting all of these APIs hooked up would let the GitHub Terraform Provider consume them too! integrations/terraform-provider-github#1632

[stevehipwell]

@AlanCitrix that is correct in theory, but as it currently stands there isn't a lot of progress on PRs over there.