Update codecov from 2.0.22 to 2.1.3 (#346)

Author: pyup-bot

requirements-testing.txt

@@ -6,7 +6,7 @@ pytest-cov==2.8.1
 autopep8==1.5.2
 mypy==0.770
 py-spy==0.3.3
-codecov==2.0.22
+codecov==2.1.3
 tox==3.15.0
 mccabe==0.6.1
 pylint==2.5.2