Introducing the skipped check run and check suite conclusion

If a check run or suite is never started, you'll see the skipped conclusion. This is a common check run conclusion for GitHub Actions that have a job using an if condition.

We created the skipped conclusion to help distinguish this type of scenario from when a check run or suite is cancelled. A check run or suite has the cancelled conclusion when the check run was planned or started but then stopped. For example, a conclusion can be cancelled due to manual intervention or possibly some service issues that cause the check run to stop.