elixir devshell: better flake

templates/devshells/elixir/flake.nix

@@ -1,9 +1,13 @@
 {
-  description = "Elixir devshel";
+  description = "Development environment";
 
   inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs";
+    nixpkgs = {
-    flake-utils.url = "github:numtide/flake-utils";
+      url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    };
+    flake-utils = {
+      url = "github:numtide/flake-utils";
+    };
   };
 
   outputs =
@@ -15,13 +19,17 @@
     flake-utils.lib.eachDefaultSystem (
       system:
       let
+        inherit (nixpkgs.lib) optional;
         pkgs = import nixpkgs { inherit system; };
+
+        elixir = pkgs.beam.packages.erlang.elixir;
+        elixir-ls = pkgs.beam.packages.erlang.elixir_ls;
       in
       {
-        devShells.default =
+        devShell = pkgs.mkShell {
-          with pkgs;
+          buildInputs = [
-          mkShell {
+            elixir
-            packages = [ beam.packages.erlang_26.elixir_1_15 ];
+          ];
         };
       }
     );