update flake.nix setup

flake.lock

@@ -0,0 +1,27 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1708296515,
+        "narHash": "sha256-FyF489fYNAUy7b6dkYV6rGPyzp+4tThhr80KNAaF/yY=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "b98a4e1746acceb92c509bc496ef3d0e5ad8d4aa",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixos-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -9,12 +9,11 @@
     self,
     nixpkgs,
   }: let
-    inherit (nixpkgs.lib) genAttrs makeBinPath;
-    eachSystem = fn:
-      genAttrs [ "x86_64-linux" ]
-      (system: fn nixpkgs.legacyPackages.${system});
+    inherit (nixpkgs.lib) genAttrs;
+    supportedSystems = ["x86_64-linux"];
+    forAllSystems = f: genAttrs supportedSystems (system: f nixpkgs.legacyPackages.${system});
   in {
-    devShells = eachSystem (_: pkgs: {
+    devShells = forAllSystems (pkgs: {
       default = pkgs.mkShell {
         buildInputs = with pkgs; [nim openssl];
       };