Automate release announcement on twitter

[Ocramius]

Feature Request

I find myself always having to announce a release on twitter after closing a milestone.

While that's nice (added visibility), it is also something that could maybe be automated, although unsure how to formulate a meaningful tweet from it.

Q	A
New Feature	yes
RFC	yes
BC Break	no

[weierophinney]

As long as the admin key is used for the release step, we can use an existing action: https://github.com/marketplace/actions/github-twittction#release-event