flake.lock: Update (#375)

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/5c24cf2f0a12ad855f444c30b2421d044120c66f' (2024-04-19)
  → 'github:NixOS/nixpkgs/63c3a29ca82437c87573e4c6919b09a24ea61b0f' (2024-05-02)
• Updated input 'pre-commit-hooks':
    'github:cachix/pre-commit-hooks.nix/40e6053ecb65fcbf12863338a6dcefb3f55f1bf8' (2024-04-12)
  → 'github:cachix/pre-commit-hooks.nix/2849da033884f54822af194400f8dff435ada242' (2024-04-30)
• Updated input 'rust-overlay':
    'github:oxalica/rust-overlay/67e961704b80454f1ba6595b02e26afc9af4cdce' (2024-04-20)
  → 'github:oxalica/rust-overlay/b37d96b614c38922674fd8d81ebc2fe807667a5b' (2024-05-04)

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