chore(flake): update lock (#69)

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/fd16bb6d3bcca96039b11aa52038fafeb6e4f4be?narHash=sha256-LJbHQQ5aX1LVth2ST%2BKkse/DRzgxlVhTL1rxthvyhZc%3D' (2024-04-20)
  → 'github:NixOS/nixpkgs/d6f6eb2a984f2ba9a366c31e4d36d65465683450?narHash=sha256-Yg5D5LhyAZvd3DZrQQfJAVK8K3TkUYKooFtH1ulM0mw%3D' (2024-04-27)
• Updated input 'pre-commit-hooks':
    'github:cachix/pre-commit-hooks.nix/40e6053ecb65fcbf12863338a6dcefb3f55f1bf8?narHash=sha256-nMirxrGteNAl9sWiOhoN5tIHyjBbVi5e2tgZUgZlK3Y%3D' (2024-04-12)
  → 'github:cachix/pre-commit-hooks.nix/6fb82e44254d6a0ece014ec423cb62d92435336f?narHash=sha256-RWFafuSb5nkWGu8dDbW7gVb8FOQOPqmX/9MlxUUDguw%3D' (2024-04-24)
• Updated input 'treefmt-nix':
    'github:numtide/treefmt-nix/49dc4a92b02b8e68798abd99184f228243b6e3ac?narHash=sha256-N3QDhoaX%2BpaWXHbEXZapqd1r95mdshxToGowtjtYkGI%3D' (2024-04-01)
  → 'github:numtide/treefmt-nix/c6aaf729f34a36c445618580a9f95a48f5e4e03f?narHash=sha256-Qv4RBm4LKuO4fNOfx9wl40W2rBbv5u5m%2BwhxRYUMiaA%3D' (2024-04-25)

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