Update duckdb index files

.gitattributes

@@ -58,3 +58,4 @@ vesteinn--babylm/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 vesteinn--babylm/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 default/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 default/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
+default/train/index.duckdb filter=lfs diff=lfs merge=lfs -text

default/train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:b1a6cd007b02f6a039f05465edc8b279432585a006f4758383df7b572025a3b0
+size 816066560