Fix DescribeConfigsResponse_v1 config_source (#150)

Co-authored-by: Ryar Nyah <[email protected]>

Author: wbarnha

kafka/protocol/admin.py

@@ -719,7 +719,7 @@ class DescribeConfigsResponse_v1(Response):
                 ('config_names', String('utf-8')),
                 ('config_value', String('utf-8')),
                 ('read_only', Boolean),
-                ('is_default', Boolean),
+                ('config_source', Int8),
                 ('is_sensitive', Boolean),
                 ('config_synonyms', Array(
                     ('config_name', String('utf-8')),