Merge pull request #146 from rethinkdb/dependabot/pip/pytest-cov-2.8.1

Bump pytest-cov from 2.7.1 to 2.8.1

Author: gabor-boros

requirements.txt

@@ -1,7 +1,7 @@
 async-generator==1.10; python_version>="3.6"
 codacy-coverage==1.3.11
 mock==3.0.5
-pytest-cov==2.7.1
+pytest-cov==2.8.1
 pytest-tornasync; python_version >= '3.5'
 pytest-trio==0.5.2; python_version>="3.6"
 pytest==4.5.0