Update the regex and add test cases.
(There are some xfails here for cases that the regex is not currently
handling. It's too strict for IPv6 domains at the moment.)
Closes: https://github.com/docker/docker-py/issues/3195
Related: https://github.com/opencontainers/distribution-spec/pull/498
Signed-off-by: Sven Kieske <kieske@osism.tech>
Signed-off-by: Milas Bowman <milas.bowman@docker.com>
Co-authored-by: Milas Bowman <milas.bowman@docker.com>