[chore] flake.lock: update inputs

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/a3f9ad65a0bf298ed5847629a57808b97e6e8077' (2024-10-12)
  → 'github:NixOS/nixpkgs/c0b1da36f7c34a7146501f684e9ebdf15d2bebf8' (2024-10-14)
• Updated input 'nixvim':
    'github:nix-community/nixvim/619e24366e8ad34230d65a323d26ca981bfa6927' (2024-10-13)
  → 'github:nix-community/nixvim/429f2e8d1aa61181c0ec72bdafe022fbb6a092d6' (2024-10-15)
• Updated input 'unstable':
    'github:NixOS/nixpkgs/5633bcff0c6162b9e4b5f1264264611e950c8ec7' (2024-10-09)
  → 'github:NixOS/nixpkgs/a3c0b3b21515f74fd2665903d4ce6bc4dc81c77c' (2024-10-14)