Migrating to `grantbirki/command`

[nobe4]

This issue is used to track the migration of this project to @GrantBirki's ownership.

Context

Grant has been the main (and let's be frank only) dev on this codebase since its inception. It is now clear that Grant's old team can't maintain the project with the same efficacy. So we're going to transition the project to grantbirki/command over the next couple of weeks.

Plan

Our main concern is breaking existing workflows and preventing people from doing their work. This repository will stay available for anyone who wants to still use version 2.0.3 and below.

In that sense, @GrantBirki has forked the repo and will be maintaining it moving forward.

1. Open a PR on github/command to update the README + add a log WARN: github/command is archived, please migrate to grantbirki/command, see issue #1234
2. Release a new version with this change on github/command, let's say version 2.1.0.
3. @GrantBirki will make a release on grantbirki/command of the same version number 2.1.0 so that migrating is as simple as

-   use: github/command@2.1.0
+   use: grantbirki/command@2.1.0

4. Wait a couple of weeks and see how many people have transitioned.
5. If there is no report of anything going bad, archive github/command.

_{ℹ️ This plan will be updated as time goes on.}