Fix who gets sent emails of failed builds

[mattwthompson]

When a build fails, GitHub Actions defaults to sending a notification (and/or email) to the last committer to that repository. So, for example, I'm the last committer to CMILES, so I get the emails for the nightly build failures (known issue openforcefield/cmiles#39). This criterion is inconsistent, and instead we should configure each repo to have a single (or few) maintainer(s) who get these notifications and are responsible for investigating.

I'm actually not sure if this is configurable technically, the best I could find in the docs doesn't satisfy this. I recalling seeing "email this person" type of content in a CI YAML before, but maybe that was Travis.

I know we've spent a lot of time configuring Actions lately, but from my perspective, this is the only thing missing for a unified structure across the organization.

[jaimergp]

Yep, I dislike this too. I would like to have something that at leases does something like using the code_owners file to choose who to email (as mentioned in this thread). This is specially useful with cron jobs. Maybe a Slack channel could be set up for the cron job notifications?