Merge pull request #4381 from tk0miya/reduce_DeprecationWarning_on_testing

test: Reduce DeprecationWarning on testing (from docutils)

setup.cfg

@@ -44,6 +44,10 @@ incremental = True
 check_untyped_defs = True
 warn_unused_ignores = True
 
+[tool:pytest]
+filterwarnings =
+    ignore::DeprecationWarning:docutils.io
+
 [coverage:run]
 branch = True
 source = sphinx