fix config name

NLVR2.py

@@ -51,7 +51,7 @@ class NLVR2Dataset(datasets.GeneratorBasedBuilder):
     VERSION = datasets.Version("1.0.0")
 
 
-    DEFAULT_CONFIG_NAME = "Default"
+    DEFAULT_CONFIG_NAME = "default"
 
     def _info(self):
         return datasets.DatasetInfo(
@@ -72,7 +72,7 @@ class NLVR2Dataset(datasets.GeneratorBasedBuilder):
 
     def _split_generators(self, dl_manager):
         urls = {
-            "Default": {
+            "default": {
                 "train": os.path.join(_URL_JSON,  f'{_SPLITS["train"]}.json'),
                 "validation": os.path.join(_URL_JSON, f'{_SPLITS["validation"]}.json'),
                 "test1": os.path.join(_URL_JSON, f'{_SPLITS["test"]}1.json'),