requirements-test: Pin pytest to < 7.0.0
pytest v7.0.0 removed _pytest.tmpdir.TempdirFactory, which is used by some of the pytest plugins we use.
Migrated from D7084 (view on Phabricator)
pytest v7.0.0 removed _pytest.tmpdir.TempdirFactory, which is used by some of the pytest plugins we use.
Migrated from D7084 (view on Phabricator)