FIS changelog update (#5614)

* FIS changelog update

* Fix versions

Author: maksymmalyhin

FirebaseInstallations/CHANGELOG.md

@@ -1,4 +1,10 @@
-# v1.1.2 -- M69
+# v1.3.0 -- Unreleased
+
+- [changed] Mac OS Keychain storage changes: use a unique (per app) Keychain Service name to isolate Keychain items for different Mac OS applications.
+  NOTE: Installation Identifiers created by previous versions will be reset on Mac OS which can affect e.g. A/B Testing variants or debug device targeting for Firebase Messaging.
+  iOS, TVOS and watchOS Installation Identifiers will not be affected. (#5603)
+
+# v1.2.0 -- M69
 
 - [changed] Keychain key-value storage refactored to `GoogleUtilities`. (#5329)