SUMO-258848: updates changelog for analytics_tier fix

Author: raghavxk

CHANGELOG.md

@@ -1,6 +1,9 @@
 ## X.Y.Z (Unreleased)
 * Add new change notes here
 
+BUG FIXES:
+* Prevent user-initiated updates to the analytics_tier field in the partition resource, while allowing Terraform to reconcile state changes resulting from backend-driven updates (e.g., Flex migrations).
+
 ENHANCEMENTS:
 * Improve error message when an API URL is constructed with missing parameters