Move pytest_plugins to top-level conftest

https://docs.pytest.org/en/stable/deprecations.html#pytest-plugins-in-non-top-level-conftest-files

Author: selfisekai

test/conftest.py

@@ -13,6 +13,9 @@
 import pytest
 
 
+pytest_plugins = ['b2sdk.v3.testing']
+
+
 @pytest.hookimpl
 def pytest_configure(config):
     config.addinivalue_line(

test/integration/conftest.py

@@ -47,9 +47,6 @@
 GENERAL_BUCKET_NAME_PREFIX = 'clitst'
 
 
-pytest_plugins = ['b2sdk.v3.testing']
-
-
 @pytest.fixture(scope='session', autouse=True)
 def summary_notes(request, worker_id):
     capmanager = request.config.pluginmanager.getplugin('capturemanager')