fix: remove `flake-utils` follows attribute
`flake-utils` doesn't use `nixpkgs` as an input.
inputs = {
nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
flake-utils.url = "github:numtide/flake-utils";
- flake-utils.inputs.nixpkgs.follows = "nixpkgs";
rust-overlay.url = "github:oxalica/rust-overlay";
rust-overlay.inputs.nixpkgs.follows = "nixpkgs";
rust-overlay.inputs.flake-utils.follows = "flake-utils";
