Update duckdb index files

.gitattributes

@@ -17,3 +17,4 @@ mnli/test_matched/index.duckdb filter=lfs diff=lfs merge=lfs -text
 mnli/test_mismatched/index.duckdb filter=lfs diff=lfs merge=lfs -text
 mnli/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 mnli/validation_matched/index.duckdb filter=lfs diff=lfs merge=lfs -text
+mnli/validation_mismatched/index.duckdb filter=lfs diff=lfs merge=lfs -text

mnli/validation_mismatched/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:9dc7ae8af5015be5f621a3235509e8963345886371b1ad361803bafa7282e41b
+size 3682304