Add "concurrency" to GitHub Actions

[Yay295]

This will cancel outdated jobs in favor of new jobs. So if you push some changes, and then push some more changes while the first changes are still being tested, the first tests will be cancelled in favor of the new tests.

Also if you reset to the previous commit and force push that, it will actually un-cancel the previously cancelled tests for that commit.

https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#concurrency
https://docs.github.com/en/actions/learn-github-actions/contexts#github-context

[hugovk]

I'm good with this, we just added this to the CI at work.

We have something similar with Travis CI:

And AppVeyor:

The key difference is already-running builds are not cancelled for Travis (and not configurable) or AppVeyor (configurable but we haven't done so).

We can allow already-running builds to continue with GHA using cancel-in-progress: true or omitting it.

But I'm tempted to let it cancel, we have a pretty big CI matrix nowadays.

[radarhere]

Suggested change

	concurrency:
	group: ${{ github.workflow }}-${{ github.ref }}
	cancel-in-progress: true
	jobs:
	jobs:

I don't think this is necessary, as stale only runs once a day.

[hugovk]

This and tidelift.yml can also be triggered manually via workflow_dispatch:, so potentially could have more than one in the queue at once.

But I've no strong opinion either way.

[radarhere]

Suggested change

	concurrency:
	group: ${{ github.workflow }}-${{ github.ref }}
	cancel-in-progress: true
	jobs:
	jobs:

I don't think this is necessary, as Tidelift Align only runs once a day.

[radarhere]

Suggested change

	concurrency:
	group: ${{ github.workflow }}-${{ github.ref }}
	cancel-in-progress: true
	jobs:
	jobs:

Feel free to give thoughts on this, but... I kind of don't want to cancel the release drafter?

[hugovk]

It doesn't really matter as it only takes about 15s, but it's safe to cancel as we only need it to run once:

when it runs it looks at the current state of merged PRs and overwrites the previous draft.

[hugovk]

Although two different runs from two different merges will have different ${{ github.ref }} so won't be cancellable.

However, manual triggers via workflow_dispatch could have the same ref. Again, no strong opinion either way for this.