Update CHANGELOG for MPS 3.0.0.

Author: Gnuxie

CHANGELOG.md

@@ -11,6 +11,21 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Added
+
+- Support for Synapse admin endpoint for querying the block status of
+  a room
+
+- Synapse admin endpoint for shutdown V2
+
+- Synapse admin endpoint for room details.
+
+### Changed
+
+- Support for MPS's new SHA256HashReverser in the `RoomStateManagerFactory`.
+
 ## [2.10.1] - 2025-03-03
 
 ### Fixed