Update duckdb index files

.gitattributes

@@ -55,3 +55,4 @@ saved_model/**/* filter=lfs diff=lfs merge=lfs -text
 bem/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 bem/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 bem/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
+fon/train/index.duckdb filter=lfs diff=lfs merge=lfs -text

fon/train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:851969c2d0c6d062e1104568888a421b7c0f87dc42bf3e7d7c14278b87ec4a8d
+size 1060864