`nix flake check` had these warnings:
trace: warning: Module argument `nodes.client.config` is deprecated. Use `nodes.client` instead.
trace: warning: Module argument `nodes.client.config` is deprecated. Use `nodes.client` instead.
trace: warning: The option `services.openssh.permitRootLogin' defined in `/nix/store/3m3hfpmbjdf4w39qfjami7ljhvhczay1-source/tests/nixos/nix-copy.nix' has been renamed to `services.openssh.settings.PermitRootLogin'.
trace: warning: Module argument `nodes.http_dns.config` is deprecated. Use `nodes.http_dns` instead.
trace: warning: Module argument `nodes.github.config` is deprecated. Use `nodes.github` instead.
trace: warning: Module argument `nodes.sourcehut.config` is deprecated. Use `nodes.sourcehut` instead.
https://hydra.nixos.org/build/235888160
This is needed because Nixpkgs now contains dangling symlinks
(pkgs/test/nixpkgs-check-by-name/tests/symlink-invalid/pkgs/by-name/fo/foo/foo.nix).