docs: add announcement about major release and package name change

Author: dpopp07

README.md

@@ -11,7 +11,6 @@ Node.js client library to use the Watson APIs.
 
 <details>
   <summary>Table of Contents</summary>
-
   * [Before you begin](#before-you-begin)
   * [Installation](#installation)
   * [Usage](#usage)
@@ -47,6 +46,13 @@ Node.js client library to use the Watson APIs.
 
 </details>
 
+## ANNOUNCEMENTS!
+### New Major Version
+The new major version, `v4` has been released. The major new feature in this release is native support for Promises. There are some breaking changes - use the [migration guide](https://github.com/watson-developer-cloud/node-sdk/blob/master/UPGRADE-4.0.md) to navigate any changes that affect your code.
+
+### Package Rename
+This package has been moved under the name `ibm-watson`. The package is still available at `watson-developer-cloud`, but that will no longer receive updates. Use `ibm-watson` to stay up to date.
+
 ## Before you begin
 * You need an [IBM Cloud][ibm-cloud-onboarding] account.