chore(deps): update dependency langchain-google-vertexai to v3.0.3 (#367)

Author: renovate-bot

samples/index_tuning_sample/requirements.txt

@@ -1,3 +1,3 @@
 langchain-community==0.4.1
 langchain-google-cloud-sql-pg==0.14.1
-langchain-google-vertexai==3.0.1
+langchain-google-vertexai==3.0.3