Update coverage to 6.4.2

[pyup-bot]

This PR updates coverage from 6.4.1 to 6.4.2.

Changelog

6.4.2

--------------------------

- Updated for a small change in Python 3.11.0 beta 4: modules now start with a
line with line number 0, which is ignored.  This line cannnot be executed, so
coverage totals were thrown off.  This line is now ignored by coverage.py,
but this also means that truly empty modules (like ``__init__.py``) have no
lines in them, rather than one phantom line.  Fixes `issue 1419`_.

- Internal debugging data added to sys.modules is now an actual module, to
avoid confusing code that examines everything in sys.modules.  Thanks,
Yilei Yang (`pull 1399`_).

.. _pull 1399: https://github.com/nedbat/coveragepy/pull/1399
.. _issue 1419: https://github.com/nedbat/coveragepy/issues/1419


.. _changes_6-4-1:

Links

• PyPI: https://pypi.org/project/coverage
• Changelog: https://pyup.io/changelogs/coverage/
• Repo: https://github.com/nedbat/coveragepy