docs: add announcements section and pi deprecation

Author: mediumTaj

README.md

@@ -25,6 +25,12 @@ Use this SDK to build Watson-powered applications in Unity.
 
 </details>
 
+## ANNOUNCEMENTS!
+### Personality Insights Deprecation
+IBM® will begin sunsetting IBM Watson™ Personality Insights on 1 December 2020. For a period of one year from this date, you will still be able to use Watson Personality Insights. However, as of 1 December 2021, the offering will no longer be available.
+
+As an alternative, we encourage you to consider migrating to IBM Watson™ [Natural Language Understanding](https://cloud.ibm.com/docs/natural-language-understanding), a service on IBM Cloud® that uses deep learning to extract data and insights from text such as keywords, categories, sentiment, emotion, and syntax to provide insights for your business or industry. For more information, see About Natural Language Understanding.
+
 ## Before you begin
 Ensure that you have the following prerequisites: