deps: update flake.lock (#121)

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/fe51d34885f7b5e3e7b59572796e1bcb427eccb1?narHash=sha256-qmmFCrfBwSHoWw7cVK4Aj%2Bfns%2Bc54EBP8cGqp/yK410%3D' (2025-05-22)
  → 'github:nixos/nixpkgs/59138c7667b7970d205d6a05a8bfa2d78caa3643?narHash=sha256-7gGa49iB9nCnFk4h/g9zwjlQAyjtpgcFkODjcOQS0Es%3D' (2025-05-31)

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

Author: mrcjkb