Ubuntu command fails for Ubuntu 24.04 noble numbat

[bootchk]

This command does not work:

- !Ubuntu noble

Instead, you can use:

- !UbuntuRelease { codename: noble, url: http://cloud-images.ubuntu.com/noble/current/noble-server-cloudimg-amd64-root.tar.xz}

Apparently, Ubuntu has changed the URL of their server of cloud images.

Also, apparently what "cloud image" means has changed. The downloaded artifact seems to be built expressly to be run in a VM, and sometimes seems to print messages about no VM being detected.