deps: update flake.lock (#124)

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/6afe187897bef7933475e6af374c893f4c84a293?narHash=sha256-K9yBph93OLTNw02Q6e9CYFGrUhvEXnh45vrZqIRWfvQ%3D' (2025-06-14)
  → 'github:nixos/nixpkgs/076e8c6678d8c54204abcb4b1b14c366835a58bb?narHash=sha256-1ovgdmuDYVo5OUC5NzdF%2BV4zx2uT8RtsgZahxidBTyw%3D' (2025-06-20)

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

Author: mrcjkb