ci: disable warnings output in pytest

setup.cfg

@@ -1,6 +1,6 @@
 [pytest]
 python_files = test*.py
-addopts = --tb=native -p no:doctest
+addopts = --tb=native -p no:doctest -p no:warnings
 norecursedirs = bin dist docs htmlcov script hooks node_modules .* {args}
 looponfailroots = src tests
 selenium_driver = phantomjs