Update duckdb index files

.gitattributes

@@ -103,3 +103,4 @@ iwslt2017-nl-en/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-nl-ro/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-ro-it/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-nl-en/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
+iwslt2017-ja-en/train/index.duckdb filter=lfs diff=lfs merge=lfs -text

iwslt2017-ja-en/train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:cfde10a865cd8adf046c825d7381e5fa268d914ed26d5aff7effcc6b64bc1e8d
+size 26750976