Add our own GitHub Action for Scala Steward
Add our own GitHub Action for Scala Steward

The public instance of Scala Steward run by Frank Thomas, the creator of Scala Steward, was shutdown
in [June 2022](https://github.com/scala-steward-org/repos/issues/1029), so we need to run our own instance!

This is the GitHub App I've created for it to ran as:

https://github.com/organizations/scanamo/settings/apps/scanamo-scala-steward

scanamo/scanamo