Update changelog

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Added
+
+- Introduced the option to update the cash balance of an account when adding a activity
+
 ## 1.265.0 - 2023-05-01
 
 ### Changed
@@ -15,10 +21,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Fixed the missing platform name in the allocations by platform chart on the allocations page
 
-### Added
-
-- Introduced the option to update cash balance of account when adding one activity
-
 ## 1.264.0 - 2023-05-01
 
 ### Added