Add charges warning

Author: imforster

lambda/README.md

@@ -7,6 +7,15 @@ This document describes how to use Lambda with Aurora DSQL
 - You must have installed npm v8.5.3 or higher.
 - You must have installed zip v3.0 or higher.
 
+## ⚠️ Important
+
+- Running this code might result in charges to your AWS account.
+- We recommend that you grant your code least privilege. At most, grant only the
+  minimum permissions required to perform the task. For more information, see
+  [Grant least privilege](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html#grant-least-privilege).
+- This code is not tested in every AWS Region. For more information, see
+  [AWS Regional Services](https://aws.amazon.com/about-aws/global-infrastructure/regional-product-services).
+
 # Create a new function in AWS Lambda.
 
 1. Sign in to the AWS Management Console and open the AWS Lambda console at [https://console.aws.amazon.com/lambda/](https://console.aws.amazon.com/lambda/)