Update pytest-cov to 2.9.0

[pyup-bot]

This PR updates pytest-cov from 2.8.1 to 2.9.0.

Changelog

2.9.0

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

* Fixed ``RemovedInPytest4Warning`` when using Pytest 3.10.
Contributed by Michael Manganiello in `354 <https://github.com/pytest-dev/pytest-cov/pull/354>`_.
* Made pytest startup faster when plugin not active by lazy-importing.
Contributed by Anders Hovmöller in `339 <https://github.com/pytest-dev/pytest-cov/pull/339>`_.
* Various CI improvements.
Contributed by Daniel Hahler in `363 <https://github.com/pytest-dev/pytest-cov/pull/>`_ and
`364 <https://github.com/pytest-dev/pytest-cov/pull/364>`_.
* Various Python support updates (drop EOL 3.4, test against 3.8 final).
Contributed by Hugo van Kemenade in
`336 <https://github.com/pytest-dev/pytest-cov/pull/336>`_ and
`367 <https://github.com/pytest-dev/pytest-cov/pull/367>`_.
* Changed ``--cov-append`` to always enable ``data_suffix`` (a coverage setting).
Contributed by Harm Geerts in
`387 <https://github.com/pytest-dev/pytest-cov/pull/387>`_.
* Changed ``--cov-append`` to handle loading previous data better
(fixes various path aliasing issues).
* Various other testing improvements, github issue templates, example updates.
* Fixed internal failures that are caused by tests that change the current working directory by
ensuring a consistent working directory when coverage is called.
See `306 <https://github.com/pytest-dev/pytest-cov/issues/306>`_ and
`coveragepy881 <https://github.com/nedbat/coveragepy/issues/881>`_

Links

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

[codecov]

Codecov Report

Merging #349 into develop will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop     #349   +/-   ##
========================================
  Coverage    81.34%   81.34%           
========================================
  Files           72       72           
  Lines         2776     2776           
========================================
  Hits          2258     2258           
  Misses         518      518           

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