Retain but deprecate kafka.errors.ConnectionError for compatibility

Author: dpkp

kafka/errors.py

@@ -456,6 +456,10 @@ class KafkaConnectionError(KafkaError):
     invalid_metadata = True
 
 
+class ConnectionError(KafkaConnectionError):
+    """Deprecated"""
+
+
 class BufferUnderflowError(KafkaError):
     pass