Update CHANGELOG.md

Author: JuanFranDevo

CHANGELOG.md

@@ -4,7 +4,7 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
-## [5.1.2-rc2] - 2023-03-21
+## [5.1.2rc2] - 2023-03-21
 ### Added
  * Sender: NonBlocking Socket support added
  * `responses` dependency open from ==0.22.0 to >=0.22.0