Update duckdb index files

.gitattributes

@@ -11,3 +11,4 @@ default/train/0000.parquet filter=lfs diff=lfs merge=lfs -text
 default/validation/0000.parquet filter=lfs diff=lfs merge=lfs -text
 default/test/0000.parquet filter=lfs diff=lfs merge=lfs -text
 default/test/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:fbda7503d7091c646ce7b17c6b9b2cf0c5d8bf7491438cb05f17073f22970ef2
+size 52441088