Adding callout about serverless URL for local setup

Author: ajosh0504

docs/30-dev-env/3-setup-pre-reqs.mdx

@@ -29,3 +29,11 @@ db[COLLECTION_NAME]
 
 </div>
 </details>
+
+:::caution
+If running the lab locally, you will need to manually set the value of the `SERVERLESS_URL` variable as follows:
+
+```python
+SERVERLESS_URL = "https://vtqjvgchmwcjwsrela2oyhlegu0hwqnw.lambda-url.us-west-2.on.aws/"
+```
+:::