Update duckdb index files

.gitattributes

@@ -55,3 +55,4 @@ Rosenberg--webnlg/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 Rosenberg--webnlg/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 Rosenberg--webnlg/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 default/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
+default/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text

default/validation/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:2e0407ca1b82a94ff4a12ced5ab8fd943856e3961d6264ed8357e5fd9c1794a0
+size 1323008