- Only recommend and not require the installation of python-h2 because it is
seriously broken and prevents any other Python software to run correctly with -bb.
(See also: https://github.com/python-hyper/h2/issues/1236)
This also matches upstream's setup.py which lists h2 as optional
dependency in extra_requires.

Note: python-httpx:test won't build in my home project but the .spec change is trivial.