deps: update flake.lock (#127)

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/c860cf0b3a0829f0f6cf344ca8de83a2bbfab428?narHash=sha256-4E7wWftF1ExK5ZEDzj41%2B9mVgxtuRV3wWCId7QAYMAU%3D' (2025-07-04)
  → 'github:nixos/nixpkgs/2a2130494ad647f953593c4e84ea4df839fbd68c?narHash=sha256-Q82Ms%2BFQmgOBkdoSVm%2BFBpuFoeUAffNerR5yVV7SgT8%3D' (2025-07-08)

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

Author: mrcjkb