flake.lock: Update (#132)

Flake lock file updates:

• Updated input 'neovim-nightly':
    'github:neovim/neovim/c45d1e32a92f5027fe12038b856509efe5c158fb?dir=contrib' (2023-12-02)
  → 'github:neovim/neovim/0d885247b03439ee3aff4c0b9ec095a29bb21759?dir=contrib' (2023-12-03)
• Updated input 'neovim-nightly/flake-utils':
    'github:numtide/flake-utils/a1720a10a6cfe8234c0e93907ffe81be440f4cef' (2023-05-31)
  → 'github:numtide/flake-utils/ff7b65b44d01cf9ba6a71320833626af21126384' (2023-09-12)

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