[`simple-build`](https://github.com/cachix/install-nix-action/blob/d2155ff37c047d116f743ef203fbbc2af48b6dd9/.github/workflows/test.yml#L9-L24), for example, runs only on nixos-20.03. Would it make sense to use the matrix to also run it on [recent releases](https://github.com/NixOS/nixpkgs/branches/all?query=nixos-)?