chore(flake): Ethereum.nix use its proprietary nixpkgs-unstable version

Due to an issue with rustc in the more recent version.

• Updated input 'ethereum-nix/nixpkgs-unstable':
    'github:nixos/nixpkgs/b69de56fac8c2b6f8fd27f2eca01dcda8e0a4221?narHash=sha256-f0SBJz1eZ2yOuKUr5CA9BHULGXVSn6miBuUWdTyhUhU%3D' (2024-10-10)
  → 'github:nixos/nixpkgs/9c513fc6fb75142f6aec6b7545cb8af2236b80f5?narHash=sha256-bu0xbu2Z6DDzA9LGV81yJunIti6r7tjUImeR8orAL/I%3D' (2024-06-25)

Author: MartinNikov

flake.lock

@@ -72,7 +72,13 @@
       url = "github:metacraft-labs/ethereum.nix";
       inputs = {
         nixpkgs.follows = "nixos-2311";
-        nixpkgs-unstable.follows = "nixpkgs-unstable";
+
+        # Comment out the unstable packages temporarily since the `rustc-wrapper`
+        # version in our unstable version is `1.80.1` and the compilation fails
+        # with an error, however the `rustc-wrapper` version in the `ethereum-nix`
+        # unstable version is `1.78.0`.
+        # nixpkgs-unstable.follows = "nixpkgs-unstable";
+
         flake-parts.follows = "flake-parts";
         flake-utils.follows = "flake-utils";
         systems.follows = "systems";