build(deps-dev): bump coverage from 4.0.3 to 5.3.1 (#40)

Bumps [coverage](https://github.com/nedbat/coveragepy) from 4.0.3 to 5.3.1.
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](nedbat/coveragepy@coverage-4.0.3...coverage-5.3.1)

Signed-off-by: dependabot[bot] <support@github.com>

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

requirements_dev.txt

@@ -18,7 +18,7 @@ mock==3.0.5
 requests==2.25.1
 u-msgpack-python==2.7.1
 six==1.12.0
-coverage==4.0.3
+coverage==5.3.1
 splunk-sdk==1.6.14
 future==0.18.2
 -r requirements_addon_specific.txt