New review comment by klardotsh on void-packages repository

https://github.com/void-linux/void-packages/pull/32349#discussion_r683815806

Comment:
From what I can tell in the thread, this isn't being actively worked on, there's no ETA of when or if it may ever get worked on, and for that matter, got punted from a milestone to generic "backlog".

It looks safe to assume that at least for the near term (I'd guess at least 6mo), this is a Docker-only tool, and thus should depend on `docker`.