Viewer: name the split 'eval'

README.md

@@ -6,11 +6,11 @@ pretty_name: RelBench dbinfer datasets
 configs:
 - config_name: databases
   data_files:
-  - split: databases
+  - split: eval
     path: databases.parquet
 - config_name: tasks
   data_files:
-  - split: tasks
+  - split: eval
     path: tasks.parquet
 ---