Adds a new `checkout` step intended to replace `git checkout` by
actually checking out the correct revision when running commands.
Adds a new `upload_artifact` step that uploads an artifact to a package
specific prefix. Primarily intended for supporting Go dependency
archives, but could also be used for anything.
Added `net-vpn/tailscale` using this new functionality.
Adds an automatic updater to handle updating ebuilds in this repository
based on the latest version available on the remote.
Also puts `elint` in this repo since I've been working on this one more
than the former.
