update whats-new.md with new pricing

Author: jr-MS

articles/cognitive-services/Anomaly-Detector/whats-new.md

@@ -15,6 +15,9 @@ We've also added links to some user-generated content. Those items will be marke
 
 ## Release notes
 
+### Jan 2023
+* Multivariate Anomaly Detection starts charging since January 10th, 2023. The pricing details see in [pricing page](https://azure.microsoft.com/pricing/details/cognitive-services/anomaly-detector/).
+
 ### Dec 2022
 * Multivariate Anomaly Detection SDK is updated to match with GA API for four languages.