add agenix

[ryantm]

agenix is a popular secrets management tool for NixOS.

https://github.com/ryantm/agenix

[ncfavier]

$ nix run nixos-search -- --json flake github:ryantm/agenix
Using saved setting for 'extra-substituters = https://nixos-search.cachix.org' from ~/.local/share/nix/trusted-settings.json.
Using saved setting for 'extra-trusted-public-keys = nixos-search.cachix.org-1:1HV3YF8az4fywnH+pAd+CXFEdpTXtv9WpoivPi+H70o=' from ~/.local/share/nix/trusted-settings.json.
[2023-04-27T08:17:43Z ERROR command_run] command 'nix eval --json --no-allow-import-from-derivation --no-write-lock-file -f '/nix/store/98f5014z23jnh0cg3j5gg52ipljsv0p8-flake-info/assets/commands/flake_info.nix' -I nixpkgs=channel:nixpkgs-unstable --override-flake input-flake github:ryantm/agenix --argstr flake github:ryantm/agenix all' failed: exit status: 1
    stdout:

    stderr:
    error: attribute 'pkgs' missing

           at /nix/store/6k86n3h3s0prrhbc84s800qrp5zwhqbi-source/lib/modules.nix:507:28:

              506|         builtins.addErrorContext (context name)
              507|           (args.${name} or config._module.args.${name})
                 |                            ^
              508|       ) (lib.functionArgs f);
    (use '--show-trace' to show detailed location information)

Error: Getting flake info caused an error: Failed to gather information about github:ryantm/agenix

Caused by:
    command 'nix eval --json --no-allow-import-from-derivation --no-write-lock-file -f '/nix/store/98f5014z23jnh0cg3j5gg52ipljsv0p8-flake-info/assets/commands/flake_info.nix' -I nixpkgs=channel:nixpkgs-unstable --override-flake input-flake github:ryantm/agenix --argstr flake github:ryantm/agenix all' failed: exit status: 1

This error is caused by using pkgs in an option default, which isn't available. Use defaultText and literalExpression to provide a textual representation of the default value.