Show workflow name in for workflow_job.completed Github webhook

[narumi147]

I selected the Check Suites type webhook to report to discord, and have two valid workflows. Here is the message:

the two wekflows are for the same commit. I cannot distinguish them by message itself.

So I suggest to change format from
[repo] GitHub Actions checks success on main
to
[repo] GitHub Actions [workflow_name] checks success on main