This is a requirement for nixpkgs 21.05, or else evaluation will fail
with:
Exactly one of users.users.${name}.isSystemUser and users.users.${name}.isNormalUser must be set.
No combination of systemd options could be identified to automatically restart
systemd-tmpfiles-setup.service whenever pulse.service gets started, so
deploying systemd.services.pulse to a running system will leave pulse.service
in a failed state.