Update duckdb index files

.gitattributes

@@ -74,3 +74,4 @@ iwslt2017-en-ja/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-en-ar/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-en-de/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-en-it/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
+iwslt2017-en-zh/train/index.duckdb filter=lfs diff=lfs merge=lfs -text

iwslt2017-en-zh/train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:be4f1586ccec9569b9c2bded6ac6b9e2f777d5a5fc6479613e317fff2aa962a8
+size 25964544