flake.lock: Update

Flake lock file updates:

• Updated input 'haskell-flake':
    'github:srid/haskell-flake/f8f38ecd259338167cc0c85fd541479297a315af?narHash=sha256-eUMmQKXjt4WQq%2BIBscftg/Y9bXWiOYhasfeH5Yb9Psc%3D' (2024-07-21)
  → 'github:srid/haskell-flake/b6ae9406c4c1abb2664a88396aafaa296379b542?narHash=sha256-Fezl0Xfg2v6hkVgQnB3B5UT64lKCbr7eFMYRrqOtTJg%3D' (2024-08-11)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/81610abc161d4021b29199aa464d6a1a521e0cc9?narHash=sha256-TcXjLVNd3VeH1qKPH335Tc4RbFDbZQX%2Bd7rqnDUoRaY%3D' (2024-08-02)
  → 'github:nixos/nixpkgs/8b908192e64224420e2d59dfd9b2e4309e154c5d?narHash=sha256-nk0RaUB5f68BwtXAYy3WAjqFhVKqIl9Z89RGycTa2vk%3D' (2024-08-15)
• Updated input 'treefmt-nix':
    'github:numtide/treefmt-nix/768acdb06968e53aa1ee8de207fd955335c754b7?narHash=sha256-uru7JzOa33YlSRwf9sfXpJG%2BUAV%2BbnBEYMjrzKrQZFw%3D' (2024-07-30)
  → 'github:numtide/treefmt-nix/4a6d7dccf80a1aa2d04cfaa88d9e5511542a2486?narHash=sha256-6Sx%2B/VhRPLR%2BkRf6rnNUFMQ66DUz1DMYajixYUe%2BCUU%3D' (2024-08-14)