Update README with upcoming change warning (#302)

Author: JEAxero

README.md

@@ -1,13 +1,37 @@
 <p align="center"><img width=60% src="docs/media/ReactSDK-Logo.png">
 
-# React SDK
+<hr />
+<h1 style="color: red">IMPORTANT – PLEASE READ!</h1>
+
+<h3>On <strong>April 24, 2023</strong>, there will be a <strong>significant update</strong> to the React SDK <strong>main</strong> branch.</h3>
+<br />
+
+**We strongly recommend that existing SDK users** clone the update into a new working folder locally. The existing SDK folder structure has significantly changed and may result in the deletion of folders in your local working copy.   Some recommendations on how to migrate your existing components to the new SDK will be published on the release date, along with a comprehensive set of documentation updates describing the new capabilities (navigate to **https://docs.pega.com** and then search for 'Constellation SDKs').
+
+**For any SDK user who wants to remain on the old main branch**, check out the following branch which will be created on April 24, 2023 before updates are made to the **main** branch:
+
+&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;**release/8.8.10**
+
+The updates that will be made to the main branch reflect a significant repackaging of the React SDK that addresses 2 key improvements:
+
+1.	The **DX Component Builder tool** for creating custom DX components is **fully integrated** into the SDK. There is no longer a need to create custom components with a separate tool (in a separate folder structure) and then copy the components into the SDK.
+
+2.	The Pega-provided React SDK components have been moved into an npm package (@pega/react-sdk-components) that is a new dependency for the React SDK. This means that a new React SDK project provides an **empty component structure** that will only contain the SDK user’s code without the clutter of the Pega provided components. SDK users will add their components to the project by creating custom components or overriding existing Pega components. It also allows for easier updates to the Pega-provided components since updates to the npm package won’t directly affect the SDK user’s code.
+
+A new repo (from which the @pega/react-sdk-components and @pega/react-sdk-overrides packages are created) will be public and open source soon. When it becomes public, the source code for the React SDK components will be available there. Until then, the source code for the components
+can be found in the node_modules/@pega/react-sdk-overrides/lib directory.
+
+<hr />
+
+<h1> React SDK</h1>
 
 The **React SDK** provides Pega customers with the ability to build DX components that connect Pega’s ConstellationJS Engine APIs with a design system other than Pega Cosmos.
 
 The React SDK differs from out-of-the-box Constellation design system because it provides and demonstrates the use of a React design system that is not the Pega **Constellation** design system. The alternative design system used in this React SDK is **Material UI** (https://mui.com/).
 
 The React SDK is built on a new and modernized UI technology stack (the Constellation JavaScript Engine and Constellation JavaScript API). Many additional SDK features are planned for 1H 2022 to expand the scope of supported use cases.
 
+<br />
 
 <br>
 
@@ -21,7 +45,7 @@ The **MediaCo** sample application is already configured as a Constellation appl
 
 The **React SDK** has been tested with:
 - node 18.12.1/18.13.0
-- npm 8.19.2/8.19.3 
+- npm 8.19.2/8.19.3
 
 Future updates to the SDK will support more recent LTS versions of node as Constellation supports them.
 
@@ -236,8 +260,8 @@ You can test both **Portal** and **Embedded** scenarios by executing the followi
 <br>
 
 ### Check Node/NPM versions
-Currently, the SDK supports Node 18.* (LTS/Hydrogen) and has been tested with node 18.12.1/18.13.0 and npm 8.19.2/8.19.3, respectively. 
-Future updates to the SDK will support more recent LTS versions of node as Constellation supports them. 
+Currently, the SDK supports Node 18.* (LTS/Hydrogen) and has been tested with node 18.12.1/18.13.0 and npm 8.19.2/8.19.3, respectively.
+Future updates to the SDK will support more recent LTS versions of node as Constellation supports them.
 
 ### Verify/update Cross Origin Resource Sharing (CORS) Infinity record