Build notifications on slack

[oliverbarnes]

It'd be great to track build statuses on #github-dev-activity, specially since we need act quickly on smoke test failures (either reverting the failing commit or submitting a fix)

[oliverbarnes]

From a quick search I found this action for it. The steps for which seem a little verbose, but it's a start, and there's probably other options out there:

https://github.com/marketplace/actions/slack-notify-build

[jinjagit]

How would this be better than the ticks we get for successful CI on push/merge? Because we could have a dedicated slack channel = easier to track (without other messages pushing the checks out of view)? Or this would be a regular check (say, hourly)?

[jinjagit]

Notes on the action: A Slack bot token is required to use this action, and the associated app must be granted permission to post in the channel, private group or DM you specify.