Update duckdb index files

.gitattributes

@@ -59,3 +59,4 @@ sw_amps_math/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 pd_news/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 ccby_law/partial-train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 ccby_s2orc/partial-train/index.duckdb filter=lfs diff=lfs merge=lfs -text
+ccby_stackexchange/partial-train/index.duckdb filter=lfs diff=lfs merge=lfs -text

ccby_stackexchange/partial-train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:afa6cc7ede4120316790f2f187d5ebace515193b8f06e26f122668115a0d59a4
+size 9647697920