Build error with latest nixos-unstable

[BonusPlay]

When attempting to build current main branch under current nixos-unstable I get the following error

error: evaluation aborted with the following error message: 'lib.customisation.callPackageWith: Function called without required argument "nodejs_21" at /nix/store/qs161vzi5kh527nyhfpjldkcshgh790y-source/components/frontend.nix:5, did you mean "nodejs_20", "nodejs_22" or "nodejs_14"?'

nodejs_21 was dropped recently (https://github.com/NixOS/nixpkgs/commit/12c19fa317f73b5aea5e32f60e2cd00222e2e831). The fix should nicely tie-in with #18.