Reorder split names

Reorder split names in the YAML metadata to be aligned with the order in the loading script.
See: https://github.com/huggingface/datasets/issues/5258

README.md

@@ -27,15 +27,15 @@ dataset_info:
   - name: label
     dtype: string
   splits:
-  - name: test
-    num_bytes: 6852864
-    num_examples: 12000
   - name: train
     num_bytes: 18878686
     num_examples: 32000
   - name: validation
     num_bytes: 5765303
     num_examples: 8000
+  - name: test
+    num_bytes: 6852864
+    num_examples: 12000
   download_size: 8658581
   dataset_size: 31496853
 ---