[chore] flake.lock: update inputs

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/44a71ff39c182edaf25a7ace5c9454e7cba2c658' (2024-09-10)
  → 'github:NixOS/nixpkgs/e65aa8301ba4f0ab8cb98f944c14aa9da07394f8' (2024-09-11)
• Updated input 'nixvim':
    'github:nix-community/nixvim/4e5bd1d79bb88b98e4d23241096989373150112c' (2024-09-13)
  → 'github:nix-community/nixvim/61be7a6eed7b6e70db9731cdf32d6a3e163cee73' (2024-09-15)
• Updated input 'nixvim/flake-parts':
    'github:hercules-ci/flake-parts/567b938d64d4b4112ee253b9274472dc3a346eb6' (2024-09-01)
  → 'github:hercules-ci/flake-parts/bcef6817a8b2aa20a5a6dbb19b43e63c5bf8619a' (2024-09-12)