fix flake8 error related to zarr_version fixture

Author: grlee77

zarr/tests/test_sync.py

@@ -15,7 +15,8 @@
 from zarr.storage import (DirectoryStore, KVStore, atexit_rmtree, init_array,
                           init_group)
 from zarr.sync import ProcessSynchronizer, ThreadSynchronizer
-from zarr.tests.test_attrs import TestAttributes, zarr_version
+# zarr_version fixture must be imported although not used directly here
+from zarr.tests.test_attrs import TestAttributes, zarr_version  # noqa
 from zarr.tests.test_core import TestArray
 from zarr.tests.test_hierarchy import TestGroup