fix the black and flake8 conflict by removing trailing comma

Author: ChrisZhangProdigy

setup.cfg

@@ -2,5 +2,5 @@
 max-line-length = 88
 extend-ignore =
     # See https://github.com/PyCQA/pycodestyle/issues/373
-    E203, E231
+    E203,
 no-isort-config = True

tests/test_graphql_client.py

@@ -85,7 +85,7 @@ def test_execute_query_with_headers(self, post_mock):
         """Sends a graphql POST request with headers."""
         client = GraphqlClient(
             endpoint="http://www.test-api.com/",
-            headers={"Content-Type": "application/json", "Existing": "123",},
+            headers={"Content-Type": "application/json", "Existing": "123"},
         )
         query = ""
         client.execute(query=query, headers={"Existing": "456", "New": "foo"})
@@ -186,7 +186,7 @@ async def test_execute_query_with_headers(self, mock_post):
         mock_post.return_value.__aenter__.return_value.json = CoroutineMock()
         client = GraphqlClient(
             endpoint="http://www.test-api.com/",
-            headers={"Content-Type": "application/json", "Existing": "123",},
+            headers={"Content-Type": "application/json", "Existing": "123"},
         )
         query = ""