Update duckdb index files

.gitattributes

@@ -56,3 +56,4 @@ thu-coai--esconv/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 thu-coai--esconv/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 thu-coai--esconv/test/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:b09de168089201b11a02def8df97fc68aa44755150be593aeff1b771db175539
+size 6041600