Update coverage to 4.5.4

[pyup-bot]

This PR updates coverage from 4.5.3 to 4.5.4.

Changelog

4.5.4

---------------------------
- Multiprocessing support in Python 3.8 was broken, but is now fixed. Closes
`issue 828`_.
.. _issue 828: https://github.com/nedbat/coveragepy/issues/828
.. _changes_453:

Links

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

[codecov-io]

Codecov Report

❗ No coverage uploaded for pull request base (master@319ffa4). Click here to learn what that means.
The diff coverage is n/a.

@@ Coverage Diff @@## master #142 +/- ##
=======================================
Coverage ? 100% =======================================
Files ? 12 Lines ? 116 Branches ? 0 =======================================
Hits ? 116 Misses ? 0 Partials ? 0

---

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[pyup-bot]

Closing this in favor of #205