Auto merge of #1667 - RalfJung:cron-fail-notification, r=RalfJung
Auto merge of #1667 - RalfJung:cron-fail-notification, r=RalfJung

send Zulip notification when cron job fails

Let's see if this works...

rust-lang/miri,rust-lang/miri,rust-lang/miri,rust-lang/miri