chore: model upgrade in samples (#304)

Author: vishwarajanand

samples/langchain_on_vertexai/prebuilt_langchain_agent_template.py

@@ -75,7 +75,7 @@ def similarity_search(query: str) -> list[Document]:
 # Uncomment to test locally
 
 # app = reasoning_engines.LangchainAgent(
-#     model="gemini-pro",
+#     model="gemini-2.0-flash-001",
 #     tools=[similarity_search],
 #     model_kwargs={
 #         "temperature": 0.1,
@@ -92,7 +92,7 @@ def similarity_search(query: str) -> list[Document]:
 
 remote_app = reasoning_engines.ReasoningEngine.create(
     reasoning_engines.LangchainAgent(
-        model="gemini-pro",
+        model="gemini-2.0-flash-001",
         tools=[similarity_search],
         model_kwargs={
             "temperature": 0.1,

samples/langchain_on_vertexai/retriever_agent_with_history_template.py

@@ -151,7 +151,7 @@ def query(self, input: str, session_id: str) -> str:
 
 # Uncomment to test locally
 # app = PostgresAgent(
-#     model="gemini-pro",
+#     model="gemini-2.0-flash-001",
 #     project=PROJECT_ID,
 #     region=REGION,
 #     instance=INSTANCE,
@@ -173,7 +173,7 @@ def query(self, input: str, session_id: str) -> str:
 
 remote_app = reasoning_engines.ReasoningEngine.create(
     PostgresAgent(
-        model="gemini-pro",
+        model="gemini-2.0-flash-001",
         project=PROJECT_ID,
         region=REGION,
         instance=INSTANCE,

samples/langchain_on_vertexai/retriever_chain_template.py

@@ -123,7 +123,7 @@ def query(self, input: str) -> str:
 # Uncomment to test locally
 
 # app = PostgresRetriever(
-#     model="gemini-pro",
+#     model="gemini-2.0-flash-001",
 #     project=PROJECT_ID,
 #     region=REGION,
 #     instance=INSTANCE,
@@ -143,7 +143,7 @@ def query(self, input: str) -> str:
 
 remote_app = reasoning_engines.ReasoningEngine.create(
     PostgresRetriever(
-        model="gemini-pro",
+        model="gemini-2.0-flash-001",
         project=PROJECT_ID,
         region=REGION,
         instance=INSTANCE,