Update duckdb index files

.gitattributes

@@ -6,3 +6,4 @@ citesum/validation/0000.parquet filter=lfs diff=lfs merge=lfs -text
 citesum/test/0000.parquet filter=lfs diff=lfs merge=lfs -text
 citesum/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 citesum/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
+citesum/test/index.duckdb filter=lfs diff=lfs merge=lfs -text

citesum/test/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:1de3ad84aceb33eb344844ffdd793443b8091a2da08c3cb8234cd073360d2a1a
+size 18886656