flake: update inputs (#150)

Flake lock file updates:

• Updated input 'nixos-cosmic':
    'github:lilyinstarlight/nixos-cosmic/0a12841c81a192a6f76a51d9f07ad6bc22206cce?narHash=sha256-H3lZV8A1cn2TopvJnjHmSLbzj12X9nlcVZuEWHHW%2BiE%3D' (2024-12-15)
  → 'github:lilyinstarlight/nixos-cosmic/a364e6a5e9eb93253daf93c747b150e31e09b13c?narHash=sha256-c/7bsbMcVMb8c4wiLA142ZQfL08U8qYJROGf9NCkfQE%3D' (2024-12-17)
• Updated input 'nixos-cosmic/rust-overlay':
    'github:oxalica/rust-overlay/81fe5c27cb281a9b796d7ad05ad9179e5bd0c78d?narHash=sha256-1%2Br8wYucn8kp9d/IBW1uYGs31QQmSZURElsiOTx65xM%3D' (2024-12-14)
  → 'github:oxalica/rust-overlay/83ee8ff74d6294a7657320f16814754c4594127b?narHash=sha256-0aLx44yMblcOGpfFXKCzp2GhU5JaE6OTvdU%2BJYrXiUc%3D' (2024-12-16)

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