flake.lock: Update

Flake lock file updates:

• Updated input 'flake-utils':
    'github:numtide/flake-utils/ff7b65b44d01cf9ba6a71320833626af21126384' (2023-09-12)
  → 'github:numtide/flake-utils/4022d587cbbfd70fe950c1e2083a02621806a725' (2023-12-04)
• Updated input 'gitignore':
    'github:hercules-ci/gitignore.nix/9e21c80adf67ebcb077d75bd5e7d724d21eeafd6' (2023-09-07)
  → 'github:hercules-ci/gitignore.nix/43e1aa1308018f37118e34d3a9cb4f5e75dc11d5' (2023-12-29)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/f5c27c6136db4d76c30e533c20517df6864c46ee' (2023-11-30)
  → 'github:NixOS/nixpkgs/63143ac2c9186be6d9da6035fa22620018c85932' (2024-01-02)
• Updated input 'zig-overlay':
    'github:mitchellh/zig-overlay/1815ef2d0451b1121a6a91051da84906fcb06f99' (2023-12-01)
  → 'github:mitchellh/zig-overlay/b97c02c5de441db91f6de78db1e0077b36e3c869' (2024-01-05)