Revert "flake-update: Get the nixpkgs/lib subtree only"

This reverts commit e807eea9e8.

dev/flake-module.nix

@@ -15,32 +15,6 @@
       "." = { };
       "dev" = { };
     };
-    effect.settings = {
-      # Only fetch the `lib` subtree.
-      # NOTE: Users don't have to do this. They are recommended to use follows
-      #       and just use the `nixpkgs` they're already fetching anyway.
-      #       It doesn't have to be `lib/` only!
-      git.update.script = lib.mkBefore ''
-        echo 'Fetching nixpkgs-lib tree'
-        branch="nixos-unstable"
-        mkdir ~/nixpkgs
-        git -C ~/nixpkgs init
-        git -C ~/nixpkgs remote add origin https://github.com/NixOS/nixpkgs.git
-        git -C ~/nixpkgs fetch origin --filter=blob:none --depth=1 "$branch"
-        commit="$(git -C ~/nixpkgs rev-parse FETCH_HEAD)"
-        tree="$(git -C ~/nixpkgs rev-parse FETCH_HEAD:lib)"
-
-        echo 'Adjusting nixpkgs-lib.url'
-        sed -i flake.nix -e \
-          's^    nixpkgs-lib\.url = ".*^    nixpkgs-lib\.url = "https://github.com/NixOS/nixpkgs/archive/'$tree'.tar.gz"; # '$commit' /lib from '$branch'^'
-        git diff
-        grep -F "$tree" flake.nix >/dev/null || {
-          echo 'failed to write new tree to flake.nix'
-          exit 1
-        }
-        git commit flake.nix -m 'flake.nix: Update nixpkgs-lib tree'
-      '';
-    };
   };
 
   perSystem = { config, pkgs, ... }: {