Librarian Bot: Add language metadata for dataset (#2)

- Librarian Bot: Add language metadata for dataset (37bec921231918682c3b9fb9dd2a022a8188966f)


Co-authored-by: Librarian Bot (Bot) <librarian-bot@users.noreply.huggingface.co>

README.md

@@ -1,3 +1,5 @@
 ---
+language:
+- ja
 license: apache-2.0
 ---