fix: add nixos-raspberrypi to outputs

flake.nix

@@ -28,7 +28,7 @@
     self.submodules = true;
   };
 
-  outputs = { self, nixpkgs, nixpkgs-uconsole, agenix, lix, nixos-uconsole, nixos-hardware, ... }@inputs:
+  outputs = { self, nixpkgs, nixpkgs-uconsole, agenix, lix, nixos-uconsole, nixos-raspberrypi, nixos-hardware, ... }@inputs:
     let
       system = "x86_64-linux";
       keys = import ./lib/keys.nix;