Prep for doing a 1.3 compose (1.1 and 1.2 were not usable)
Fix the compose tag to use f38-compose, so we pick up the builds that
are overrides from the nightly/regular composes.
Fix the image label to include Beta in it instead of being date based
like the nightly ones.
Signed-off-by: Kevin Fenzi <kevin@scrye.com>