Update Nix flake

Author: rien

api/shell.nix

@@ -1,6 +1,6 @@
 { pkgs ? import <nixpkgs> { }, system ? builtins.currentSystem, ... }:
 let
-  dev = fetchTarball "https://github.com/chvp/devshell/archive/main.tar.gz";
+  dev = fetchTarball "https://github.com/numtide/devshell/archive/main.tar.gz";
   devshell = pkgs.devshell or (import dev { inherit system; });
   ruby = pkgs.ruby_3_2;
 in

flake.lock

@@ -11,8 +11,8 @@
     devshell = {
       url = "github:numtide/devshell";
       inputs = {
-        systems.follows = "systems";
         nixpkgs.follows = "nixpkgs";
+        flake-utils.follows = "flake-utils";
       };
     };
   };