Remove flake-utils dependency

flake.lock

@@ -1,37 +1,23 @@
 {
   "nodes": {
-    "flake-utils": {
-      "locked": {
-        "lastModified": 1676283394,
-        "narHash": "sha256-XX2f9c3iySLCw54rJ/CZs+ZK6IQy7GXNY4nSOyu2QG4=",
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "rev": "3db36a8b464d0c4532ba1c7dda728f4576d6d073",
-        "type": "github"
-      },
-      "original": {
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "type": "github"
-      }
-    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1677229269,
-        "narHash": "sha256-awE2w6oi9rzQ8qj1lwKEDm6qIA0a239fiB+AyPjXR2w=",
+        "lastModified": 1773046814,
+        "narHash": "sha256-3CEw64UyzEk5QjfbcXNIl4TfmIpa2oY+duuo6aiawcU=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "7d0ed7f2e5aea07ab22ccb338d27fbe347ed2f11",
+        "rev": "0c6c0dd2469abaa216599bb19bbf77a328af6564",
         "type": "github"
       },
       "original": {
-        "id": "nixpkgs",
-        "type": "indirect"
+        "owner": "NixOS",
+        "ref": "nixos-unstable-small",
+        "repo": "nixpkgs",
+        "type": "github"
       }
     },
     "root": {
       "inputs": {
-        "flake-utils": "flake-utils",
         "nixpkgs": "nixpkgs"
       }
     }

flake.nix

@@ -1,14 +1,25 @@
 {
-  description = "";
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable-small";
 
-  inputs.flake-utils.url = "github:numtide/flake-utils";
-
-  outputs = { self, nixpkgs, flake-utils }:
-    flake-utils.lib.eachDefaultSystem
-      (system:
-        let pkgs = nixpkgs.legacyPackages.${system}; in
+  outputs =
+    { self, nixpkgs, ... }:
+    let
+      system = "x86_64-linux";
+    in
     {
-          devShell = import ./shell.nix { inherit pkgs; };
-        }
-      );
+      devShells."${system}".default =
+        let
+          pkgs = import nixpkgs {
+            inherit system;
+          };
+        in
+        pkgs.mkShell {
+          packages = with pkgs; [
+            clang
+            platformio
+          ];
+
+          shellHook = "";
+        };
+    };
 }

shell.nix

@@ -1,5 +0,0 @@
-{ pkgs ? import <nixpkgs> { } }:
-
-with pkgs;
-
-mkShell { buildInputs = [ platformio clang ]; }