flake.lock: Update

Flake lock file updates:

• Updated input 'nixpkgs':
    'https://api.flakehub.com/f/pinned/NixOS/nixpkgs/0.1.533189%2Brev-87828a0e03d1418e848d3dd3f3014a632e4a4f64/018b0dc8-e84f-7c59-b5d6-16849c3b2074/source.tar.gz?narHash=sha256-YXUNI0kLEcI5g8lqGMb0nh67fY9f2YoJsILafh6zlMo%3D' (2023-10-06)
  → 'https://api.flakehub.com/f/pinned/NixOS/nixpkgs/0.1.565234%2Brev-bd645e8668ec6612439a9ee7e71f7eac4099d4f6/018cd1c6-60f9-7044-815c-a3e3c3a8ff3d/source.tar.gz?narHash=sha256-RtDKd8Mynhe5CFnVT8s0/0yqtWFMM9LmCzXv/YKxnq4%3D' (2024-01-02)