flake.lock: Update

Flake lock file updates:

• Updated input 'flake-parts':
    'github:hercules-ci/flake-parts/f7b3c975cf067e56e7cda6cb098ebe3fb4d74ca2' (2024-03-01)
  → 'github:hercules-ci/flake-parts/9126214d0a59633752a136528f5f3b9aa8565b7d' (2024-04-01)
• Updated input 'flake-parts/nixpkgs-lib':
    'github:NixOS/nixpkgs/1536926ef5621b09bba54035ae2bb6d806d72ac8?dir=lib' (2024-02-29)
  → 'github:NixOS/nixpkgs/d8fe5e6c92d0d190646fb9f1056741a229980089?dir=lib' (2024-03-29)
• Updated input 'nixpkgs':
    'github:NixOS/nixpkgs/44d0940ea560dee511026a53f0e2e2cde489b4d4' (2024-03-23)
  → 'github:NixOS/nixpkgs/fd281bd6b7d3e32ddfa399853946f782553163b5' (2024-04-03)
• Updated input 'poetry2nix':
    'github:fpletz/poetry2nix/274e157bbb6223c00fe14b74f5234ce27e135e3d' (2024-03-24)
  → 'github:fpletz/poetry2nix/926e709b33fec798fb8b7814ee5152061f7d4118' (2024-04-06)