When the compose is configured to include any container image, it just
followed the provided URL. This is not particularly reproducible. If the
image spec contains a tag, it may point to different images at different
time.
This commit adds a step to validating the configuration that will query
the registry and replace the tag with a digest.
This makes it more reproducible, and also fixes a problem where changing
container image would not stop ISO reuse. There's still a chance of
non-container file changing and not forcing the reuse, but that is not
very common.
JIRA: RHELCMP-14381
JIRA: RHELCMP-14465
Signed-off-by: Lubomír Sedlář <lsedlar@redhat.com>
3ed09991c1