docs: [skip ci] add nlc deprecation notice

Author: mediumTaj

README.md

@@ -15,6 +15,11 @@ Node.js client library to use the Watson APIs.
 
 ## Announcements
 
+### Natural Language Classifier deprecation
+On 9 August 2021, IBM announced the deprecation of the Natural Language Classifier service.The service will no longer be available from 8 August 2022. As of 9 September 2021, you will not be able to create new instances. Existing instances will be supported until 8 August 2022. Any instance that still exists on that date will be deleted.
+
+As an alternative, we encourage you to consider migrating to the Natural Language Understanding service on IBM Cloud that uses deep learning to extract data and insights from text such as keywords, categories, sentiment, emotion, and syntax, along with advanced multi-label text classification capabilities, to provide even richer insights for your business or industry. For more information, see [Migrating to Natural Language Understanding](https://cloud.ibm.com/docs/natural-language-classifier?topic=natural-language-classifier-migrating).
+
 ### Major version 6 released
 Version v6.0.0 of the SDK has been released and includes a number of breaking changes - see what's changed in the [migration guide](MIGRATION-V6.md).
 ### Updating endpoint URLs from watsonplatform.net