use sync client in test_objects

async client cannot be instantiated outside asyncio loop

validation doesn't require async client

tests/test_objects.py

@@ -3,7 +3,7 @@
 """
 
 import pytest
-from kubernetes_asyncio.client import ApiClient
+from kubernetes.client import ApiClient
 
 from kubespawner.objects import make_ingress, make_namespace, make_pod, make_pvc