flake.lock: Update (#96)

Flake lock file updates:

• Updated input 'neovim-nightly':
    'github:neovim/neovim/5f4f83ba322d2642d485669ecf762b629241d9dc?dir=contrib' (2023-10-04)
  → 'github:neovim/neovim/f67517bba30b6233bea85e1f6a8505171142d4ca?dir=contrib' (2023-10-05)
• Updated input 'pre-commit-hooks':
    'github:cachix/pre-commit-hooks.nix/033453f85064ccac434dfd957f95d8457901ecd6' (2023-10-01)
  → 'github:cachix/pre-commit-hooks.nix/66c352d33e0907239e4a69416334f64af2c685cc' (2023-10-05)

Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>