feature: send admin notification when server is updated

[kimadactyl]

Overview

Currently there's no notification when the server is updated for admins. This could result in unexpected side effects (why has X message changed? Why has Y stopped working?)

Scope

Set a message on deploy to tell admins that the server has been changed

Acceptance Criteria

• [x] Admin group chat gets a notification on successful deploy

Questions/Assumptions

• [x] What exactly should the message say?