Use changelog FIXED section

Signed-off-by: Oliver Tale-Yazdi <[email protected]>

Author: ggwpez

CHANGELOG.md

@@ -6,7 +6,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [1.1.1] 25.01.2024
 
-### Changed
+### Fixed
 
 - Fixed the lowering of Asset Hub existential deposits ([polkadot-fellows/runtimes#158](https://github.com/polkadot-fellows/runtimes/pull/158)).