Merge pull request #94 show need changes from black linter

Author: rekby

tox.ini

@@ -54,7 +54,7 @@ commands =
 skip_install = true
 deps = black
 commands =
-    black --check ydb examples tests --extend-exclude ydb/_grpc
+    black --diff --check ydb examples tests --extend-exclude ydb/_grpc
 
 [testenv:pylint]
 deps = pylint