Fix imports order in test

Author: antonmyronyuk

tests/test_summary.py

@@ -2,11 +2,10 @@
 
 import pytest
 from prometheus_client import CollectorRegistry
+from prometheus_client.exposition import generate_latest
 
 from prometheus_summary import Summary
 
-from prometheus_client.exposition import generate_latest
-
 
 @pytest.fixture()
 def registry():