CI: enable auto-cancel for GitHub Actions
It's working correctly. I got email notifications when previous jobs were canceled. What does auto-cancel do? > What does auto-cancel do?

A new commit will cancel all unfinished builds. So the CI only runs for the latest commit. thanks @fangchenli very nice! Maybe we should turn this off for the master branch. Or find a way to mark canceled jobs as 'success'. ahh yes if u can turn off for master