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/0.1.590113%2Brev-1536926ef5621b09bba54035ae2bb6d806d72ac8/018df9f0-47ef-778e-b2d9-de8f1e70489d/source.tar.gz?narHash=sha256-cy6ArO4k5qTx%2Bl5o%2B0mL9f5fa86tYUX3ozE1S%2BTxlds%3D' (2024-02-29)