python3Packages.jaraco_itertools: switch to pep518 build

pkgs/development/python-modules/jaraco_itertools/default.nix

···
 buildPythonPackage rec {
   pname = "jaraco.itertools";
   version = "6.2.1";
+  format = "pyproject";
 
   src = fetchPypi {
     inherit pname version;