tests/flake.lock: Update

Flake lock file updates:

• Updated input 'flake-parts':
    'github:hercules-ci/flake-parts/8471fe90ad337a8074e957b69ca4d0089218391d' (2024-08-01)
  → 'github:hercules-ci/flake-parts/b905f6fc23a9051a6e1b741e1438dbfc0634c6de' (2025-01-06)
• Updated input 'flake-parts/nixpkgs-lib':
    'https://github.com/NixOS/nixpkgs/archive/a5d394176e64ab29c852d03346c1fc9b0b7d33eb.tar.gz?narHash=sha256-uFf2QeW7eAHlYXuDktm9c25OxOyCoUOQmh5SZ9amE5Q%3D' (2024-08-01)
  → 'https://github.com/NixOS/nixpkgs/archive/e9b51731911566bbf7e4895475a87fe06961de0b.tar.gz?narHash=sha256-CewEm1o2eVAnoqb6Ml%2BQi9Gg/EfNAxbRx1lANGVyoLI%3D' (2025-01-01)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/a73246e2eef4c6ed172979932bc80e1404ba2d56' (2024-12-09)
  → 'github:nixos/nixpkgs/9d3ae807ebd2981d593cddd0080856873139aa40' (2025-01-29)

Author: WilliButz