Propagate 1.2.2 and 1.2.3 changelogs back to main (polkadot-fellows#294)

These two patch releases were released from their respective branches.
This PR keeps the changelog up to date on `main`.

To be merged after the release in polkadot-fellows#293 

- [x] Does not require a CHANGELOG entry

CHANGELOG.md

@@ -7,16 +7,24 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ## [Unreleased]
 
 - Add `pallet-vesting` to Asset Hubs ([polkadot-fellows/runtimes#269](https://github.com/polkadot-fellows/runtimes/pull/269))
-- Fix Kusama Coretime launch issues: import leases and fix renewals for short leases ([polkadot-fellows/runtimes#276](https://github.com/polkadot-fellows/runtimes/pull/276))
 - Remove DMP queue and allow `system::authorize_upgrade` in XCM's call filter ([polkadot-fellows/runtimes#280](https://github.com/polkadot-fellows/runtimes/pull/280))
+
+## [1.2.3] 29.04.2024
+
+### Added
+
 - Add migration to Kusama Coretime to onboard People Chain without long delay ([polkadot-fellows/runtimes#286](https://github.com/polkadot-fellows/runtimes/pull/286))
+
+### Fixed
+
 - Clean up outdated assignment in Kusama Coretime Chain state ([polkadot-fellows/runtimes#286](https://github.com/polkadot-fellows/runtimes/pull/286))
 
+## [1.2.2] 20.04.2024
+
 ### Fixed
 
-- Bumped `bp-header-chain` dependency and added migration to Polkadot Bridge Hub to unstuck
-  bridge with Kusama. Details may be found in relevant
-  [polkadot-sdk](https://github.com/paritytech/polkadot-sdk/pull/4208) PR.
+- Polkadot Bridge Hub: Unstuck bridge with Kusama ([polkadot-fellows/runtimes#277](https://github.com/polkadot-fellows/runtimes/pull/277)).
+- Fix Kusama Coretime launch issues: import leases and fix renewals for short leases ([polkadot-fellows/runtimes#276](https://github.com/polkadot-fellows/runtimes/pull/276))
 
 ## [1.2.1] 09.04.2024