Suppress deprecation warning in docutils
@@ -5,3 +5,5 @@ doctest_optionflags=ALLOW_UNICODE ELLIPSIS
filterwarnings=
ignore:Possible nested set::pycodestyle:113
ignore:Using or importing the ABCs::flake8:410
+ # workaround for https://sourceforge.net/p/docutils/bugs/348/
+ ignore:'U' mode is deprecated::docutils.io
