add challenge set CM+T

CrossWOZ.py

@@ -203,7 +203,7 @@ class CrossWOZ(datasets.GeneratorBasedBuilder):
                 },
             ),
             datasets.SplitGenerator(
-                name="challenge_CM+T",
+                name="challenge",
                 # These kwargs will be passed to _generate_examples
                 gen_kwargs={
                     "filepath": os.path.join(data_dir, "test.json"),