Update duckdb index files

.gitattributes

@@ -86,3 +86,4 @@ iwslt2017-fr-en/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-en-nl/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-en-ro/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-it-ro/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
+iwslt2017-en-zh/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text

iwslt2017-en-zh/validation/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:2e930b877c0a2799f5dab7f1adba122ad901416342ee0d182069e5ade534ab30
+size 1060864