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/0.1.616726%2Brev-7bb2ccd8cdc44c91edba16c48d2c8f331fb3d856/018f1b7a-3024-744d-92f4-1398df513980/source.tar.gz?narHash=sha256-Drmja/f5MRHZCskS6mvzFqxEaZMeciScCTFxWVLqWEY%3D' (2024-04-25)