Update duckdb index files

.gitattributes

@@ -112,3 +112,4 @@ iwslt2017-ko-en/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-nl-it/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-nl-ro/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 iwslt2017-it-ro/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
+iwslt2017-nl-en/train/index.duckdb filter=lfs diff=lfs merge=lfs -text

iwslt2017-nl-en/train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:e04a88009266ea9991709f07243662b4e4d8220d99620f0b2e15825cc783ad54
+size 23080960