[BLD] Add a concurrency group to our PR checks workflow

[eculver]

Preview Note

This is to create a discussion. I'd like to hear from others as to whether this is a desired property of our GitHub Actions configuration.

Description of changes

This adds a concurrency group for our PR checks. This solves for the case where a developer pushes a commit to a PR, the build is triggered, then shortly thereafter (any time before the triggered build completes) another build is triggered but the previous is not cancelled. This change will cancel any inflight builds when a new commit for a PR is pushed. We are only doing this for PR checks as we don't necessarily want this behavior for our merges to main.

• Improvements & Bug fixes
  • Cancels in-flight builds when new commits are pushed

Test plan

Should have no effect on existing functionality.

[github-actions]

Reviewer Checklist

Please leverage this checklist to ensure your code review is thorough before approving

Testing, Bugs, Errors, Logs, Documentation

• Can you think of any use case in which the code does not behave as intended? Have they been tested?
• Can you think of any inputs or external events that could break the code? Is user input validated and safe? Have they been tested?
• If appropriate, are there adequate property based tests?
• If appropriate, are there adequate unit tests?
• Should any logging, debugging, tracing information be added or removed?
• Are error messages user-friendly?
• Have all documentation changes needed been made?
• Have all non-obvious changes been commented?

System Compatibility

• Are there any potential impacts on other parts of the system or backward compatibility?
• Does this change intersect with any items on our roadmap, and if so, is there a plan for fitting them together?

Quality

• Is this code of a unexpectedly high quality (Readability, Modularity, Intuitiveness)

[propel-code-bot]

This PR introduces a concurrency group setting in the GitHub Actions workflow for pull request checks. The change ensures that when a new commit is pushed to an open PR, any currently running checks for previous commits are automatically canceled, preventing redundant builds. This behavior is applied only to PRs and not for merges to the main branch.

This summary was automatically generated by @propel-code-bot