Merge pull request #7633 from docker/dependabot/pip/coverage-5.2.1

Bump coverage from 5.1 to 5.2.1

requirements-dev.txt

@@ -1,5 +1,5 @@
 Click==7.1.2
-coverage==5.1
+coverage==5.2.1
 ddt==1.4.1
 flake8==3.8.3
 gitpython==2.1.15