flake.lock: Update

Flake lock file updates:

• Updated input 'git-hooks':
    'github:cachix/git-hooks.nix/c8a54057aae480c56e28ef3e14e4960628ac495b' (2024-08-23)
  → 'github:cachix/git-hooks.nix/4509ca64f1084e73bc7a721b20c669a8d4c5ebe6' (2024-08-28)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/d0e1602ddde669d5beb01aec49d71a51937ed7be' (2024-08-24)
  → 'github:NixOS/nixpkgs/71e91c409d1e654808b2621f28a327acfdad8dc2' (2024-08-28)
• Updated input 'treefmt-nix':
    'github:numtide/treefmt-nix/070f834771efa715f3e74cd8ab93ecc96fabc951' (2024-08-22)
  → 'github:numtide/treefmt-nix/3ffd842a5f50f435d3e603312eefa4790db46af5' (2024-08-28)