As part of #39309 we enabled "Vigilant Mode" for the `@renovate-bot`
author.
To give an indication to folks who are self-hosting (on GitHub.com) and
using this Git commit author, we can provide a log message to let them
know.
This does not at all stop usage of this default committer email address,
but does provide a "nudge" to folks that they may see `Unverified`
commits pop up.
Jamie Tanna