Update duckdb index files

.gitattributes

@@ -40,3 +40,4 @@ cochrane/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 cochrane/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 ms2/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 ms2/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
+ms2/train/index.duckdb filter=lfs diff=lfs merge=lfs -text

ms2/train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:acf5978566803a61ecc340e53dbbde5d387e1bbb1899b80a8b67e61ef6b288d4
+size 1311256576