Update duckdb index files

.gitattributes

@@ -71,3 +71,4 @@ iwslt2017-en-ja/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-en-de/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-en-fr/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 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-ar/train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:c6b4f6462191471314aee2b0ab5ebfd78f93a74f33e3cbd7c1da97ddb58076a9
+size 27013120