Since kernel upgrading from 'default' to 'rt kernel' has SSH
connection issue, 'install' kernel and 'upgrade' kernel must
have 'kernel-rt' included.
https://github.com/osbuild/osbuild-composer/issues/1222
Only RHEL 8.4 repo has 'rt kernel' repo, 'rt kernel' test will be
RHEL 8.4 only
We are gaining new ostree features that overlap to a great deal
with the current ones. We still need to keep the current features
for backwards compatibility, so add another test run that does the
same but using new API.
For now this simply uses the `url` parameter rather than `parent`
to build update commits. Further changes will be made in follow-up
commits.
Use `curl` rather than `composer-cli` as we have a chicken-and-egg
problem where we can't land this feature without tests, but
`composer-cli` can't add support for it without having it first in
`composer`.
