flake.lock: Update

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/8f48c9241de143e8e60a826d405fa8dec5e49343' (2024-07-01)
  → 'github:NixOS/nixpkgs/6614b28fa9bf539914306658a4cb957f068ce969' (2024-08-01)
• Updated input 'pre-commit-hooks':
    'github:cachix/pre-commit-hooks.nix/0ff4381bbb8f7a52ca4a851660fc7a437a4c6e07' (2024-06-24)
  → 'github:cachix/pre-commit-hooks.nix/f451c19376071a90d8c58ab1a953c6e9840527fd' (2024-07-15)
• Updated input 'pre-commit-hooks/nixpkgs-stable':
    'github:NixOS/nixpkgs/03d771e513ce90147b65fe922d87d3a0356fc125' (2024-06-19)
  → 'github:NixOS/nixpkgs/194846768975b7ad2c4988bdb82572c00222c0d7' (2024-07-07)