Use custom package erlang_26 for elixir_1_16

flake.nix

@@ -10,12 +10,21 @@
     flake-utils.lib.eachDefaultSystem (system:
       let
         pkgs = import nixpkgs { inherit system; };
+
+        customElixir = pkgs.elixir_1_16.override {
+          erlang = pkgs.erlang_26;
+        };
       in
       {
         devShells = rec {
           default = pkgs.mkShell {
             nativeBuildInputs = with pkgs; [
-              elixir_1_16 git inotify-tools
+              customElixir
+            ];
+
+            buildInputs = with pkgs; [
+              git
+              inotify-tools
             ];
           };
         };