docs: add link to performance section in README (#5854)

Author: trivikr

README.md

@@ -25,6 +25,9 @@ and provides step-by-step migration instructions to v3.
 To test your universal JavaScript code in Node.js, browser and react-native environments,
 visit our [code samples repo](https://github.com/aws-samples/aws-sdk-js-tests).
 
+Performance is crucial for the AWS SDK for JavaScript because it directly impacts the user experience.
+Please refer to [Performance](https://github.com/aws/aws-sdk-js-v3/tree/main/supplemental-docs/performance) section to know more.
+
 # Table of Contents
 
 1. [Getting Started](#getting-started)
@@ -41,6 +44,7 @@ visit our [code samples repo](https://github.com/aws-samples/aws-sdk-js-tests).
    1. [Abort Controller](#abort-controller)
    1. [Middleware Stack](#middleware-stack)
 1. [Working with the SDK in Lambda](#working-with-the-sdk-in-lambda)
+1. [Performance](#performance)
 1. [Install from Source](#install-from-source)
 1. [Giving feedback and contributing](#giving-feedback-and-contributing)
 1. [Release Cadence](#release-cadence)
@@ -229,6 +233,10 @@ export const handler = async (event) => {
 };
 ```
 
+## Performance
+
+Please refer to supplemental docs on [performance](https://github.com/aws/aws-sdk-js-v3/tree/main/supplemental-docs/performance) to know more.
+
 ## Install from Source
 
 All clients have been published to NPM and can be installed as described above. If you want to play with latest clients, you can build from source as follows: