deprecation notice

Author: joeyzhao2018

README.md

@@ -6,6 +6,8 @@
 [![Godoc](https://img.shields.io/badge/godoc-reference-blue.svg)](https://godoc.org/github.com/DataDog/datadog-lambda-go)
 [![License](https://img.shields.io/badge/license-Apache--2.0-blue)](https://github.com/DataDog/datadog-lambda-go/blob/main/LICENSE)
 
+> **IMPORTANT NOTICE**: This repository is being deprecated. The library has been migrated to [https://github.com/DataDog/dd-trace-go/tree/main/contrib/aws/datadog-lambda-go](https://github.com/DataDog/dd-trace-go/tree/main/contrib/aws/datadog-lambda-go). 
+
 Datadog Lambda Library for Go enables enhanced Lambda metrics, distributed tracing, and custom metric submission from AWS Lambda functions.  
 
 ## Installation