Bump coverage from 5.4 to 5.5

Bumps [coverage](https://github.com/nedbat/coveragepy) from 5.4 to 5.5.
- [Release notes](https://github.com/nedbat/coveragepy/releases)
- [Changelog](https://github.com/nedbat/coveragepy/blob/master/CHANGES.rst)
- [Commits](nedbat/coveragepy@coverage-5.4...coverage-5.5)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

requirements-ci.txt

@@ -1,6 +1,6 @@
 pytest==6.2.2
 pytest-cov==2.11.1
-coverage==5.4
+coverage==5.5
 coveralls==3.0.0
 moto==1.3.16
 boto3==1.17.12