Update duckdb index files

.gitattributes

@@ -20,3 +20,4 @@ task5-full-dialogs/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 task5-full-dialogs/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text
 task6-dstc2/test/index.duckdb filter=lfs diff=lfs merge=lfs -text
 task6-dstc2/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
+task6-dstc2/validation/index.duckdb filter=lfs diff=lfs merge=lfs -text

task6-dstc2/validation/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:d2e77933f4dee83a59e833fb244cbe78bb4b06652b9457f1756bc177811bf35a
+size 1060864