docs/cgroup-v2.md: update the distro list
docs/cgroup-v2.md: update the distro list

Signed-off-by: Akihiro Suda <10ddef0dea2a66ab193b07198faa879adcb213d8@hco.ntt.co.jp>

opencontainers/runc,opencontainers/runc,opencontainers/runc,opencontainers/runc