Update duckdb index files

.gitattributes

@@ -5,3 +5,4 @@ extractive/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 abstractive/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 abstractive/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 extractive/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
+extractive/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text

extractive/validation/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:68c4dce3d6b49eeefd5b21a3a13063d83b4c1af01c54efb016f0b7bc73aa3b12
+size 1585152