nixos/tests/nar-serve: Fix after nix version bump

Changed files
+1 -1
nixos
+1 -1
nixos/tests/nar-serve.nix
···
# Create a fake cache with Nginx service the static files
server.succeed(
-
"nix copy --to file:///var/www ${pkgs.hello}"
+
"nix --experimental-features nix-command copy --to file:///var/www ${pkgs.hello}"
)
server.wait_for_unit("nginx.service")
server.wait_for_open_port(80)