chore(deps): update samples-index_tuning_sample (#450)

Co-authored-by: Averi Kitsch <[email protected]>

Author: renovate-bot

samples/index_tuning_sample/requirements.txt

@@ -1,3 +1,3 @@
 langchain-google-alloydb-pg==0.12.0
-langchain==0.3.26
-langchain-google-vertexai==2.0.20
+langchain==0.3.27
+langchain-google-vertexai==2.0.28