Reroute Dependabot emails to a separate separate list

[Matt Sicker]

I like to follow the notifications lists because that’s where I can see code 
changes committed, PRs opened, issues opened, etc. However, Dependabot spam 
makes it nearly impossible to find. There was a recent update to the .asf.yaml 
config features that allow customizing where Dependabot shit goes. I propose we 
create another list (which I won’t subscribe to) for Dependabot-related 
notifications.