flake: update inputs (#399)

Flake lock file updates:

• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/bc947f541ae55e999ffdb4013441347d83b00feb?narHash=sha256-NOiTvBbRLIOe5F6RbHaAh6%2B%2BBNjsb149fGZd1T4%2BKBg%3D' (2024-10-04)
  → 'github:NixOS/nixpkgs/c31898adf5a8ed202ce5bea9f347b1c6871f32d1?narHash=sha256-yumd4fBc/hi8a9QgA9IT8vlQuLZ2oqhkJXHPKxH/tRw%3D' (2024-10-06)
• Updated input 'nixpkgs-stable':
    'github:NixOS/nixpkgs/ecbc1ca8ffd6aea8372ad16be9ebbb39889e55b6?narHash=sha256-PbDWAIjKJdlVg%2BqQRhzdSor04bAPApDqIv2DofTyynk%3D' (2024-10-06)
  → 'github:NixOS/nixpkgs/1bfbbbe5bbf888d675397c66bfdb275d0b99361c?narHash=sha256-a0a0M1TmXMK34y3M0cugsmpJ4FJPT/xsblhpiiX1CXo%3D' (2024-10-07)
• Updated input 'rust-overlay':
    'github:oxalica/rust-overlay/25685cc2c7054efc31351c172ae77b21814f2d42?narHash=sha256-lJMFnMO4maJuNO6PQ5fZesrTmglze3UFTTBuKGwR1Nw%3D' (2024-10-07)
  → 'github:oxalica/rust-overlay/d216ade5a0091ce60076bf1f8bc816433a1fc5da?narHash=sha256-r%2BSa1NRRT7LXKzCaVaq75l1GdZcegODtF06uaxVVVbI%3D' (2024-10-08)

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