pynq.lib import fails with pycparser ≥ 3.0: ModuleNotFoundError: No module named 'pycparser.plyparser'

[ironmanna]

Importing anything from pynq.lib fails because pynq/lib/pynqmicroblaze/rpc.py imports ParseError from pycparser.plyparser, a submodule that was removed in pycparser 3.0.

This breaks CI on every PR because tests/test_axigpio.py (and any other test that touches pynq.lib) cannot even be collected.