Short-name aliasing was introduced with Podman 2.2 as an opt-in preview
by enabling an environment variable. Now, as we're preparing for the
3.0 release, we can enable short-name aliasing by default. Opting out
can be done by configuring the `registries.conf` config file.
Please refer to the following blog post for more details:
https://www.redhat.com/sysadmin/container-image-short-names
Signed-off-by: Valentin Rothberg <rothberg@redhat.com>