nixos/k3s: add zfs to path

nixos/modules/services/cluster/k3s/default.nix

@@ -87,6 +87,7 @@ in
       description = "k3s service";
       after = mkIf cfg.docker [ "docker.service" ];
       wantedBy = [ "multi-user.target" ];
+      path = optional config.boot.zfs.enabled config.boot.zfs.package;
       serviceConfig = {
         # See: https://github.com/rancher/k3s/blob/dddbd16305284ae4bd14c0aade892412310d7edc/install.sh#L197
         Type = if cfg.role == "agent" then "exec" else "notify";