Publish releases for other platforms

[jasonrdsouza]

Right now we're only publishing releases for mac, but Go makes it easy to publish for a range of platforms. We should at least support windows and popular linux variants, ideally via the canonical package managers. Subtasks

1. script to automate creating releases for multiple platforms
   • https://help.github.com/en/github/administering-a-repository/automation-for-release-forms-with-query-parameters
   • https://developer.github.com/v3/repos/releases/
2. Add package manager support (specifically, homebrew)