flake.lock: Update

Flake lock file updates:

• Updated input 'flake-parts':
    'github:hercules-ci/flake-parts/8e8d955c22df93dbe24f19ea04f47a74adbdc5ec' (2023-07-04)
  → 'github:hercules-ci/flake-parts/59cf3f1447cfc75087e7273b04b31e689a8599fb' (2023-08-01)
• Updated input 'flake-parts/nixpkgs-lib':
    'github:NixOS/nixpkgs/4bc72cae107788bf3f24f30db2e2f685c9298dc9?dir=lib' (2023-06-29)
  → 'github:NixOS/nixpkgs/9e1960bc196baf6881340d53dccb203a951745a2?dir=lib' (2023-08-01)
• Updated input 'nixpkgs':
    'github:nixos/nixpkgs/2a9d660ff0f7ffde9d73be328ee6e6f10ef66b28' (2023-07-28)
  → 'github:nixos/nixpkgs/d680ded26da5cf104dd2735a51e88d2d8f487b4d' (2023-08-19)