Alert channel for Phone calls

Describe the solution you'd like

Checkly's existing alert channels cover almost all the mediums from which I need alerts, except for something that will ring persistently and wake me from sleep — a phone call. :)

Describe alternatives you've considered

There are more comprehensive solutions that presumably include phone call alerts, as part of their broader suites of functionality -- PagerDuty, OpsGenie, Spike, etc. I'm working on cobbling this together via Checkly webhooks and the Twilio API -- https://www.twilio.com/docs/studio/rest-api/v2/execution -- but it'd be nice if this were as simple as configuring your other channels.

Additional context

I'm not looking for comprehensive stuff like scheduling, multiple phone number support, etc. Just a simple phone call to a single number if there's an outage.

Thanks for considering!

original GH issue link https://github.com/checkly/public-roadmap/issues/199