fix imports in tests

Author: mosquito

tests/conftest.py

@@ -6,7 +6,7 @@
 
 import pamqp
 import pytest
-from aiomisc_pytest.pytest_plugin import TCPProxy
+from aiomisc_pytest import TCPProxy
 from yarl import URL
 
 from aiormq import Connection

tests/test_channel.py

@@ -3,7 +3,7 @@
 from os import urandom
 
 import pytest
-from aiomisc_pytest.pytest_plugin import TCPProxy
+from aiomisc_pytest import TCPProxy
 
 import aiormq
 from aiormq.abc import DeliveredMessage