Udev package provides the setup of systemd-timesync user in
`/usr/lib/sysusers.d/systemd-timesync.conf`, however this user is not created
as part of the installation. While this could be a considered a design choice
the unexpected behavior is that the installation of any `system-user-*` package
will also result with the creation of `systemd-timesync` user.

To my eyes udev post should call `systemd-sysusers` utility to make sure users
are created so that it is consistent with other `system-user-*` packages.

Reproducer:

podman run --rm -ti opensuse/tumbleweed:latest

# inside container
zypper in -y udev

# check systemd-timesync user is not created
cat /etc/passwd 

# install a random system-user-*
zypper in -y system-user-wwwrun

# check systemd-timesync user got created
cat /etc/passwd