flake.lock: Update (#849)

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/d0797a04b81caeae77bcff10a9dde78bc17f5661?narHash=sha256-kEsTJTUQfQFIJOcLYFt/RvNxIK653ZkTBIs4DG%2BcBns%3D' (2024-12-05)
  → 'github:NixOS/nixpkgs/5d67ea6b4b63378b9c13be21e2ec9d1afc921713?narHash=sha256-Pj39hSoUA86ZePPF/UXiYHHM7hMIkios8TYG29kQT4g%3D' (2024-12-11)
• Updated input 'rust-overlay':
    'github:oxalica/rust-overlay/66526479b295ad238843a8a7367d2da7ec102757?narHash=sha256-FEDfBpM82XGdHDbLDJC4lV%2BQXSVN1rERt1MqtBGJZds%3D' (2024-12-07)
  → 'github:oxalica/rust-overlay/81fe5c27cb281a9b796d7ad05ad9179e5bd0c78d?narHash=sha256-1%2Br8wYucn8kp9d/IBW1uYGs31QQmSZURElsiOTx65xM%3D' (2024-12-14)

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