These releases are already GA. For 9.6 and 10.0, we test them in a
scheduled GA pipeline, which runs the CI tests on GA runners, which
don't have RH VPN access. Previously, some tests in the GA pipeline
would fail, because they would use rpmrepo snapshots of nightly composes
for these releases, which are behind RH VPN. Change the test repo
definitions to use CDN repositories instead, which should fix the GA
pipeline.
Signed-off-by: Tomáš Hozza <thozza@redhat.com>