Cancel Outdated Runs now supported officially via Concurrency

[HariSekhon]

GitHub Actions has a concurrency setting that can cancel previous workflows quite easily:

https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#example-using-concurrency-to-cancel-any-in-progress-job-or-run

Is the Cancel Outdated Workflow Runs functionality obsolete or does it do something that concurrency can't?

This documentation needs to be updated either way - either to point to the use the standard mechanism or to document the difference between the two and why you'd go the 3rd party route for this today:

https://github.com/fkirc/skip-duplicate-actions#cancel-outdated-workflow-runs

[paescuj]

(Just adding some references: #149, #103)

[koppor]

This action gets important again, because merge queues (of size > 1) do not work well with cancellation. See https://github.com/orgs/community/discussions/63136 for details (and please vote up the issue).

See also #329