Compatibility with non-flakes

We also provide a couple of experimental endpoints, default.{nix,zip}.

They are intended for usage on non-flake environments.

curl https://nix-versions.alwaysdata.net/default.nix/ruby@latest -o default.nix

nix-shell https://nix-versions.alwaysdata.net/default.zip/ruby@latest -A devShell

The reason we mention them as experimental is because generating a default.nix file requires our server to download and generate a sri-checksum for fetching each tools' nixpkgs with fetchurl. Doing so can consume resources (time&network) on our server. And given that many people is moving to using flakes, we are marking non-flakes features as experimental 😃.