py-test-xdist: updated to 1.34.0

pytest-xdist 1.34.0
===================

Features
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- Make ``--pdb`` imply ``--dist no``, as the two options cannot really work together at the moment.

Bug Fixes
---------
- Fix regression with duplicated arguments via $PYTEST_ADDOPTS in 1.30.0.
- Fix ``rsyncdirs`` usage with pytest 6.0.
- Do not trigger the deprecated ``pytest_warning_captured`` in pytest 6.0+.

(adam)