Update build configuration files

flake.nix

@@ -1,25 +1,19 @@
 # Do not edit this file. It is automatically generated by https://www.oliverdavies.uk/build-configs.
-
 {
-  inputs = {
-    devshell.url = "github:numtide/devshell";
-    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-  };
+  description = "A Nix Flake for build-configs";
+
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
 
-  outputs = inputs@{ flake-parts, ... }:
-    flake-parts.lib.mkFlake { inherit inputs; } {
-      imports = [ inputs.devshell.flakeModule ];
+  outputs = { nixpkgs, ... }:
+    let
+      system = "x86_64-linux";
+      pkgs = nixpkgs.legacyPackages.${system};
 
-      systems = [ "x86_64-linux" ];
+      inherit (pkgs) mkShell;
+    in {
+      devShells.${system}.default =
+        mkShell { buildInputs = with pkgs; [ just php82 php82Packages.composer ]; };
 
-      perSystem = { config, self', inputs', pkgs, system, ... }: {
-        devshells.default = {
-          packages = with pkgs; [
-            "just"
-            "php82"
-            "php82Packages.composer"
-          ];
-        };
-      };
+      formatter.${system} = pkgs.nixfmt;
     };
 }