Support canceling workflow runs

[jsoref]

Describe the feature or problem you’d like to solve

There is a REST api for canceling workflows, but https://cli.github.com/manual/gh_workflow doesn't support it.

Proposed solution

add gh run cancel $GITHUB_RUN_ID

How will it benefit CLI and its users?

Users won't have to write their own code to construct the URL and a curl request with credentials.

Additional context

I ended up implementing this myself, but I think a lot of what I'm doing would be nicer if I wasn't hand-rolling code.

[vilmibm]

This would be a valuable addition, thanks for opening.

I'd like to see this implemented as gh run cancel and contributions are welcome; otherwise, we'll pick it up when we do the next phase of actions support.

[cristiand391]

I'd like to work on this ✋🏾

[jsoref]

@cristiand391: please do.

You're going to want to add a directory for cancel here:
https://github.com/cli/cli/tree/09b09810dd812e3ede54b59ad9d6912b946ac6c5/pkg/cmd/run

You should be able to copy one of the existing directories and adjust the code to call the cancel method. You'd of course add the function to:
https://github.com/cli/cli/blob/09b09810dd812e3ede54b59ad9d6912b946ac6c5/pkg/cmd/run/run.go

[Jolg42]

Note: this would be really useful if it could cancel many runs at the same time.

Like gh run cancel all or gh run cancel name-of-workflow

[jsoref]

Based on #3775 (comment), I suspect that would make more sense to do that as gh workflow cancel name-of-workflow.

I'm not opposed, but I don't want too much scope creep. If you don't mind, could you file a request for it separately? (Feel free to reference this so people can find it)

This initial request is based on a public endpoint that is currently not reflected in the CLI. It also has a PR that has been sitting in @vilmibm 's review queue for 20 days.

[Jolg42]

@jsoref created #3960 ✅ 👍🏼