remove --fail-under from tox (covdefaults handles this)

Committed via https://github.com/asottile/all-repos

Author: asottile

tox.ini

@@ -6,7 +6,7 @@ deps = -rrequirements-dev.txt
 commands =
     coverage erase
     coverage run -m pytest {posargs:tests}
-    coverage report --fail-under 100
+    coverage report
 
 [testenv:pre-commit]
 skip_install = true