Create GitHub Actions repository

[Starlight220]

Create a repository of GitHub Actions *.yml files useful for teams, so teams can easily set up CI/CD in their repository by copying *.yml files from there.

Having checkstyle/wpiformat there would be a good start, then possibly something a vendordep one once wpilibsuite/GradleRIO#418 is merged.

When such a repo/collection is implemented, expanding the frc-docs CI/CD section and linking to said collection would be the next step.

[Starlight220]

Another idea is adding the robot project templates as GitHub template repositories, then teams that use git can have an easier setup, including not having to use VSCode.

[prateekma]

It would also be nice if something like the snippet below was supported:

- uses: wpilibsuite/check-wpiformat@master
  name: Check WPIFormat Output

[Starlight220]

Doing this will also facilitate wpilibsuite's transition to Github Actions from Azure Pipelines.

From a quick reading of the docs, it seems that each action needs a separate repository. I can do most of the work needed with some help, given that I would have the needed permissions.

[Starlight220]

Where is wpiformat developed? I didn't see a repo for it under the wpilibsuite org.
We can add the action there.

[prateekma]

https://github.com/wpilibsuite/styleguide

[Starlight220]

I think this can be closed: discussion showed that wpiformat doesn't help most teams, and what other Actions would be useful for most teams?