Add multi-arch support using flake-utils

flake.nix

@@ -4,6 +4,7 @@
   inputs = {
     fleet-pins.url = "git+https://git.oleks.space/oleks/fleet-pins?ref=main";
     nixpkgs.follows = "fleet-pins/nixpkgs-projects";
+    flake-utils.url = "github:numtide/flake-utils";
   };
 
   outputs =
@@ -11,34 +12,37 @@
       self,
       nixpkgs,
       fleet-pins,
+      flake-utils,
       ...
     }:
-    let
-      system = "x86_64-linux";
-      pkgs = import nixpkgs { inherit system; };
-    in
-    {
-      packages.${system} = rec {
-        hello-world = pkgs.callPackage ./packages/hello-world.nix { };
-        xonsh = pkgs.callPackage ./packages/xonsh.nix { };
-        default = hello-world;
-      };
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = import nixpkgs { inherit system; };
+      in
+      {
+        packages = rec {
+          hello-world = pkgs.callPackage ./packages/hello-world.nix { };
+          xonsh = pkgs.callPackage ./packages/xonsh.nix { };
+          default = hello-world;
+        };
 
-      overlays.default = final: prev: {
-        hello-world = final.callPackage ./packages/hello-world.nix { };
-        xonsh = final.callPackage ./packages/xonsh.nix { };
-      };
+        overlays.default = final: prev: {
+          hello-world = final.callPackage ./packages/hello-world.nix { };
+          xonsh = final.callPackage ./packages/xonsh.nix { };
+        };
 
-      devShells.${system}.default = pkgs.mkShell {
-        name = "oleks-hub-shell";
-        buildInputs = [ self.packages.${system}.hello-world ];
-        nativeBuildInputs = with pkgs; [
-          nix
-          fmt
-        ];
-        shellHook = ''
-          echo "Welcome to the oleks Flake hub development shell."
-        '';
-      };
-    };
+        devShells.default = pkgs.mkShell {
+          name = "oleks-hub-shell";
+          buildInputs = [ self.packages.${system}.default ];
+          nativeBuildInputs = with pkgs; [
+            nix
+            fmt
+          ];
+          shellHook = ''
+            echo "Welcome to the oleks Flake hub development shell."
+          '';
+        };
+      }
+    );
 }