Update CHANGELOG.md

Author: Badr NASS LAHSEN

CHANGELOG.md

@@ -4,7 +4,8 @@ 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).
 
-## [1.2.18] - 2019-12-08
+## [Unreleased]
+
 ### Addded
 - Globally exclude params for webflux #228