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

@@ -33,12 +33,12 @@ dataset_info:
     sequence: string
   config_name: eurlex57k
   splits:
-  - name: test
-    num_bytes: 22046706
-    num_examples: 6000
   - name: train
     num_bytes: 167603718
     num_examples: 45000
+  - name: test
+    num_bytes: 22046706
+    num_examples: 6000
   - name: validation
     num_bytes: 21942574
     num_examples: 6000