[Actions] Opt-out from auto-cancellation

[schlamar]

There are a lot of complains about the new auto-cancellation feature (#25716) as this has a lot of unexpected side effects:

• [Actions] Support concurrency syntax #24769 (comment)
• https://forum.gitea.com/t/job-stopping-on-new-push/8142

The worst side effect: Cancel does not really work as expected on a Windows runner, as child processes are not terminated: https://gitea.com/gitea/act_runner/issues/549

Please provide an option to disable auto-cancellation feature.

[michaelhofer-slg]

I agree, this would be very helpful. We have to start the jobs manually again when merging multiple branches within a short time.

[lunny]

Related to #32751

[lyz-code]

Just to give some more context on why this is important. We're using gitea actions as part of our gitops workflow, so each commit in main triggers a version bump that updates the changelog and does a tag. To be able to do that it needs to push to main these changes, but the workflow is not able to finish because this push cancels the job.