Filter Actions workflow notifications to only send messages on failures

[pg]

Is your feature request related to a problem? Please describe.
It does not appear to be possible to filter the Actions workflow notifications such that a channel is only notified when a specific workflow fails.

(We were exploring this: https://github.com/integrations/slack#actions-workflow-notifications)

Describe the solution you'd like
My team would prefer to only have a channel notification when some certain workflows (mostly deployment related) fail.

Describe alternatives you've considered
We could have notifications for all statuses of a (deployment) workflow, but we feel that would be too noisy as we aren't concerned about the successful runs.

[robbismith]

I would suggest giving us the ability to provide what workflow states we would be notified about to give us more flexibility.

For example I would like to be notified about failed or successful jobs but not skipped ones.

[MerzDaniel]

This is a duplicate of #1563