Comment 4 for bug 1876034

Actually, upon a closer look, it appears like command-not-found has been entirely unmaintained for more than 2 years now, so efforts to get this fixed upstream, let alone backported to focal, are probably futile.
We should probably just remove this package from our base image and let the end user install some fixed fork of it from a PPA, if they need it. Luckily there's no hard dependency to it from ubuntu-standard.