flake.lock: Update

Flake lock file updates:

• Updated input 'flake-parts':
    'github:hercules-ci/flake-parts/59cf3f1447cfc75087e7273b04b31e689a8599fb' (2023-08-01)
  → 'github:hercules-ci/flake-parts/7f53fdb7bdc5bb237da7fefef12d099e4fd611ca' (2023-09-01)
• Updated input 'neovim-flake':
    'github:neovim/neovim/592a8f1e90d5abaa695280bf6d41a547b3631d0d?dir=contrib' (2023-08-31)
  → 'github:neovim/neovim/597355deae2ebddcb8b930da9a8b45a65d05d09b?dir=contrib' (2023-09-01)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/a63a64b593dcf2fe05f7c5d666eb395950f36bc9' (2023-08-30)
  → 'github:NixOS/nixpkgs/da938d190e2335209df6806ddcb982634e51918c' (2023-08-31)