docs(generative_ai): Update Grounding with Google Search sample to include dynamic retrieval (GoogleCloudPlatform#13099)

* docs(generative_ai): Update Grounding with Google Search sample to include dynamic retrieval

* Update requirements.txt

* Update requirements-test.txt

Author: holtskinner

generative_ai/grounding/requirements.txt

@@ -1,14 +1 @@
-pandas==1.3.5; python_version == '3.7'
-pandas==2.0.3; python_version == '3.8'
-pandas==2.1.4; python_version > '3.8'
-pillow==10.3.0; python_version < '3.8'
-pillow==10.3.0; python_version >= '3.8'
-google-cloud-aiplatform[all]==1.69.0
-sentencepiece==0.2.0
-google-auth==2.29.0
-anthropic[vertex]==0.28.0
-langchain-core==0.2.33
-langchain-google-vertexai==1.0.10
-numpy<2
-openai==1.30.5
-immutabledict==4.2.0
+google-cloud-aiplatform==1.78.0

generative_ai/grounding/web_example.py

@@ -36,7 +36,14 @@ def generate_text_with_grounding_web() -> GenerationResponse:
     model = GenerativeModel("gemini-1.5-flash-001")
 
     # Use Google Search for grounding
-    tool = Tool.from_google_search_retrieval(grounding.GoogleSearchRetrieval())
+    tool = Tool.from_google_search_retrieval(
+        grounding.GoogleSearchRetrieval(
+            # Optional: For Dynamic Retrieval
+            dynamic_retrieval_config=grounding.DynamicRetrievalConfig(
+                dynamic_threshold=0.7,
+            )
+        )
+    )
 
     prompt = "When is the next total solar eclipse in US?"
     response = model.generate_content(