Given we're using public container registry as the default registry,
so it would be nice to have a verification for the image's digest.
Kubernetes already supports that so user can just use format like
@sha256:xxx for those addons' tags. This patch introduces the support
for hyperkube based on podman and fedora coreos driver.
Task: 37776
Story: 2007001
Change-Id: I970c1b91254d2a375192420a9169f3a629c56ce7
(cherry picked from commit a943756aea)
5b625257d3