Implement the `/break pacman-upload-lease` command

This is a companion to https://github.com/git-for-windows/build-extra/pull/488 and https://github.com/git-for-windows/git-for-windows-automation/issues/40 (and needs the latter to be implemented).

The goal is to have an easy, [least stress-ful way](https://zachholman.com/posts/deploying-software) to address deployment problems.