Update docs/src/changelog.md

Author: odow

docs/src/changelog.md

@@ -7,7 +7,7 @@ CurrentModule = JuMP
 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).
 
-## Version 1.18.0 (December 20, 2023)
+## Version 1.18.0 (December 21, 2023)
 
 ### Added