Update coverage to 5.3

[pyup-bot]

This PR updates coverage from 5.2.1 to 5.3.

Changelog

5.3

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

- The ``source`` setting has always been interpreted as either a file path or a
module, depending on which existed.  If both interpretations were valid, it
was assumed to be a file path.  The new ``source_pkgs`` setting can be used
to name a package to disambiguate this case.  Thanks, Thomas Grainger. Fixes
`issue 268`_.

- If a plugin was disabled due to an exception, we used to still try to record
its information, causing an exception, as reported in `issue 1011`_.  This is
now fixed.

.. _issue 268: https://github.com/nedbat/coveragepy/issues/268
.. _issue 1011: https://github.com/nedbat/coveragepy/issues/1011


.. _changes_521:

Links

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