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

- Librarian Bot: Add language metadata for dataset (3c663a9e4a688cd902b6c786ca1b509ac2421e45)


Co-authored-by: Librarian Bot (Bot) <[email protected]>

README.md

@@ -1,4 +1,6 @@
 ---
+language:
+- ja
 dataset_info:
   features:
   - name: text