Update duckdb index files

.gitattributes

@@ -64,3 +64,4 @@ saved_model/**/* filter=lfs diff=lfs merge=lfs -text
 2/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 3/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 3/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
+3/train/index.duckdb filter=lfs diff=lfs merge=lfs -text

3/train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:b2623af93c200f5553df5cf575441be763da94044de3e3abb742c60f8138b49f
+size 6828032