Update pytest-cov to 4.1.0

[pyup-bot]

This PR updates pytest-cov from 4.0.0 to 4.1.0.

Changelog

4.1.0

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

* Updated CI with new Pythons and dependencies.
* Removed rsyncdir support. This makes pytest-cov compatible with xdist 3.0.
Contributed by Sorin Sbarnea in `558 <https://github.com/pytest-dev/pytest-cov/pull/558>`_.
* Optimized summary generation to not be performed if no reporting is active (for example,
when ``--cov-report=''`` is used without ``--cov-fail-under``).
Contributed by Jonathan Stewmon in `589 <https://github.com/pytest-dev/pytest-cov/pull/589>`_.
* Added support for JSON reporting.
Contributed by Matthew Gamble in `582 <https://github.com/pytest-dev/pytest-cov/pull/582>`_.
* Refactored code to use f-strings.
Contributed by Mark Mayo in `572 <https://github.com/pytest-dev/pytest-cov/pull/572>`_.
* Fixed a skip in the test suite for some old xdist.
Contributed by a bunch of people in `565 <https://github.com/pytest-dev/pytest-cov/pull/565>`_.

Links

• PyPI: https://pypi.org/project/pytest-cov
• Changelog: https://pyup.io/changelogs/pytest-cov/
• Repo: https://github.com/pytest-dev/pytest-cov