Revert "Nix: move to devshell"

This reverts commit 8c9f075a4e.

flake.nix

@@ -1,26 +1,22 @@
 {
-  description = "virtual environments";
-
-  inputs.devshell.url = "github:numtide/devshell";
+  description = "Hugo website";
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
   inputs.flake-utils.url = "github:numtide/flake-utils";
 
-  inputs.flake-compat = {
-    url = "github:edolstra/flake-compat";
-    flake = false;
-  };
-
-  outputs = { self, flake-utils, devshell, nixpkgs, ... }:
-    flake-utils.lib.eachDefaultSystem (system: {
-      devShells.default =
-        let
-          pkgs = import nixpkgs {
-            inherit system;
-
-            overlays = [ devshell.overlays.default ];
-          };
-        in
-        pkgs.devshell.mkShell {
-          imports = [ (pkgs.devshell.importTOML ./devshell.toml) ];
+  outputs =
+    { nixpkgs, flake-utils, ... }:
+    flake-utils.lib.eachDefaultSystem (
+      system:
+      let
+        pkgs = nixpkgs.legacyPackages.${system};
+      in
+      {
+        devShells.default = pkgs.mkShell {
+          packages = [
+            pkgs.go
+            pkgs.hugo
+          ];
         };
-    });
+      }
+    );
 }