update dataset card desc

README.md

@@ -14,9 +14,9 @@ configs:
   data_files:
     - split: ndd_cd8
       path: data/ndd_v0.2.tsv
-    - split: leaderboard-train
+    - split: leaderboard_train
       path: data/nip_leaderboard_train.tsv
-    - split: leaderboard-test
+    - split: leaderboard_test
       path: data/nip_leaderboard_test.tsv
 ---