Update duckdb index files

.gitattributes

@@ -81,3 +81,4 @@ iwslt2017-it-ro/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-en-ko/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-it-nl/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-en-nl/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
+iwslt2017-it-nl/train/index.duckdb filter=lfs diff=lfs merge=lfs -text

iwslt2017-it-nl/train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:866593f9f47f850a7b1319774092ea16f569d12e78f6e705e9a19a2e3ec8f0c5
+size 23080960