Update duckdb index files

.gitattributes

@@ -481,3 +481,4 @@ lua/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 parrot-internal-representation/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 propeller-spin/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
 http/train/index.duckdb filter=lfs diff=lfs merge=lfs -text
+protocol-buffer/train/index.duckdb filter=lfs diff=lfs merge=lfs -text

protocol-buffer/train/index.duckdb

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:7042d7856a33e972cdf797e6d9e9b4f30b449e741a1eae011af5cb39fbfe6553
+size 1585152