flake.lock: Update (#345)

Flake lock file updates:

• Updated input 'flake-utils':
    'github:numtide/flake-utils/dbabf0ca0c0c4bce6ea5eaf65af5cb694d2082c7' (2023-06-25)
  → 'github:numtide/flake-utils/919d646de7be200f3bf08cb76ae1f09402b6f9b4' (2023-07-11)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/3c7487575d9445185249a159046cc02ff364bff8' (2023-07-06)
  → 'github:nixos/nixpkgs/12303c652b881435065a98729eb7278313041e49' (2023-07-22)
• Updated input 'pre-commit-hooks':
    'github:cachix/pre-commit-hooks.nix/c8d18ba345730019c3faf412c96a045ade171895' (2023-07-05)
  → 'github:cachix/pre-commit-hooks.nix/eb433bff05b285258be76513add6f6c57b441775' (2023-07-18)
• Updated input 'rust-overlay':
    'github:oxalica/rust-overlay/7a29283cc242c2486fc67f60b431ef708046d176' (2023-07-08)
  → 'github:oxalica/rust-overlay/97fcdd4793778cf8e4f9007079cb9d2b836d7ea9' (2023-07-22)

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