Fix broken devShell by adding flake-utils support for multiple systems

flake.nix

@@ -1,36 +1,39 @@
 {
   description = "flake to setup the dev env required for Tandem";
-  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
   outputs =
-    { self, nixpkgs }:
-    let
-      system = "x86_64-linux";
-      pkgs = import nixpkgs {
-        inherit system;
-        config.allowUnfree = true;
-      };
-    in
-    {
-      devShells.${system}.default =
-        with pkgs;
+    { self, nixpkgs, flake-utils }:
+    flake-utils.lib.eachDefaultSystem (system:
+      let
+        pkgs = import nixpkgs {
+          inherit system;
+          config.allowUnfree = true;
+        };
+      in
+      {
+        devShells.default =
+          with pkgs;
 
-        mkShell {
-          buildInputs = [
-            go
-            gopls
-            gotools
-            vagrant
-            sqlc
-            goreleaser
-          ];
+          mkShell {
+            buildInputs = [
+              go
+              gopls
+              gotools
+              vagrant
+              sqlc
+              goreleaser
+            ];
 
-          shellHook = ''
-            export GOROOT="${pkgs.go}/share/go"
-            export GOPATH="$PWD/.go"
-            export PATH="$GOPATH/bin:$PATH"
-            export GOBIN="$GOPATH/bin"
-            source tandem.env
-          '';
-        };
-    };
+            shellHook = ''
+              export GOROOT="${pkgs.go}/share/go"
+              export GOPATH="$PWD/.go"
+              export PATH="$GOPATH/bin:$PATH"
+              export GOBIN="$GOPATH/bin"
+              source tandem.env
+            '';
+          };
+      });
 }