Email maintainers when new version released

[tfausak]

Similar to #230.

This is a good way to be notified that releasing a new version actually worked. This is especially useful when publishing packages using an automated process. Also it could be helpful as a way to notice unwanted releases, for example if an account was compromised.

Other package repositories that I use, including npm and RubyGems, have features like this.

[ysangkok]

What does "releasing a new version actually worked" mean? Did we address this with #1168? Not clear what needs to be done for this.