Update README.md

Change default config to bigfish config

README.md

@@ -35,7 +35,7 @@ dataset_info:
     num_examples: 100000
   download_size: 4787252231
   dataset_size: 28937250000
-- config_name: default
+- config_name: bigfish
   features:
   - name: observation
     dtype:
@@ -69,12 +69,12 @@ configs:
     path: bossfight/train-*
   - split: test
     path: bossfight/test-*
-- config_name: default
+- config_name: bigfish
   data_files:
   - split: train
-    path: data/train-*
+    path: bigfish/train-*
   - split: test
-    path: data/test-*
+    path: bigfish/test-*
 tags:
 - procgen
 - bigfish