Update duckdb index files

.gitattributes

@@ -1,2 +1,3 @@
 jonathanli--law-stack-exchange/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 jonathanli--law-stack-exchange/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
+jonathanli--law-stack-exchange/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text

jonathanli--law-stack-exchange/validation/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:771c7378e748df121a373f7ceb24287b6ab614397a5874cf01629a0144fa6b84
+size 1585152