[requires.io] dependency update

Author: requires

tox.ini

@@ -276,7 +276,7 @@ skip_install = True
 
 deps =
     {[testenv:coverage_report]deps}
-    codecov==2.1.7
+    codecov==2.1.8
 
 passenv =
     # See https://github.com/codecov/codecov-python/blob/master/README.md#using-tox