Update duckdb index files

.gitattributes

@@ -63,3 +63,4 @@ ccby_stackexchange/partial-train/index.duckdb filter=lfs diff=lfs merge=lfs -tex
 ccby_stackoverflow/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 ccby_wikipedia/partial-train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 pd_law/partial-train/index.duckdb filter=lfs diff=lfs merge=lfs -text
+pd_books/partial-train/index.duckdb filter=lfs diff=lfs merge=lfs -text

pd_books/partial-train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:38acdb23967ecf033f5b2b79b0c319a2822e493cea5cb8ef52d477589500067d
+size 5630603264