Update duckdb index files

.gitattributes

@@ -3,3 +3,4 @@ OGB--ogbg-molhiv/json-train.parquet filter=lfs diff=lfs merge=lfs -text
 OGB--ogbg-molhiv/train/0000.parquet filter=lfs diff=lfs merge=lfs -text
 default/train/0000.parquet 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 sha256:2374b14c1c1b33e87a45933a7e1da77fc57ac76c3ceec2d34f46b83480f680ea
+size 2371584