Suppress EncodingWarning in pytest_black. Workaround for shopkeep/pytest-black#67.

Author: jaraco

pytest.ini

@@ -17,3 +17,6 @@ filterwarnings=
 	ignore:<class 'pytest_flake8.Flake8Item'> is not using a cooperative constructor:pytest.PytestDeprecationWarning
 	ignore:The \(fspath. py.path.local\) argument to Flake8Item is deprecated.:pytest.PytestDeprecationWarning
 	ignore:Flake8Item is an Item subclass and should not be a collector:pytest.PytestWarning
+
+	# shopkeep/pytest-black#67
+	ignore:'encoding' argument not specified::pytest_black