Update broken link on README.md (#194)

Update broken link to aws lambda documentation.

Author: lplazas

Diff for: README.md

@@ -4,7 +4,7 @@
 
 This repository contains code and tools for working with Elastic APM's AWS Lambda solution.  
 
-If you're looking to get started with Elastic's AWS Lambda extension and agent instrumentation, the [AWS Lambda Extension](https://www.elastic.co/guide/en/apm/guide/current/aws-lambda-extension.html) documentation is the place to start. 
+If you're looking to get started with Elastic's AWS Lambda extension and agent instrumentation, the [AWS Lambda Extension](https://www.elastic.co/guide/en/apm/guide/current/monitoring-aws-lambda.html) documentation is the place to start. 
 
 ### Update the docs