message: Add `.gitignore` rule for nested `package-lock.json` files.
  Follows up defensively on:
diff: node_modules
  lib
  +# Only the top-level of the monorepo should govern package locks,
  +# not the individual package directories. (Keep in mind that currently
  +# `npm install` should not be run within the `packages/*` directories.)
  +packages/*/package-lock.json
  +
  # Visual Studio Code workspace settings
  .vscode/*
  !.vscode/settings.json
  