Now a single unified kernel image is built using a new CoreOS
specific functionality added in the efibootguard UKI stub to
automatically insert root=PARTLABEL=rootfs0 (or rootfs1) in the
kernel command line
BREAKING CHANGE: coreos-image-uki.bbclass now only generate a
single kernel image named kernel-${MACHINE}.efi
Merge in ICO/coreos from update_subomdules_2023-06-19_10-44 to master
* commit '8c73a56d98c8c78b6ca26c370f77130e32cd676c':
fix(3rd-party): automatic update of CoreOS submodules
BREAKING CHANGE: bblayers.conf / bblayers.conf.sample of project
using CoreOS should be adapted to use external-layers instead
of layers for each moved layers