python: Replace universal_newlines with text.

This is supported in Python ≥ 3.7.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

zerver/openapi/test_curl_examples.py

@@ -98,9 +98,7 @@ def test_generated_curl_examples_for_success(client: Client) -> None:
                 try:
                     # We split this across two lines so if curl fails and
                     # returns non-JSON output, we'll still print it.
-                    response_json = subprocess.check_output(
-                        generated_curl_command, universal_newlines=True
-                    )
+                    response_json = subprocess.check_output(generated_curl_command, text=True)
                     response = json.loads(response_json)
                     assert response["result"] == "success"
                 except (AssertionError, Exception):