Update docs/src/changelog.md

Author: odow

docs/src/changelog.md

@@ -7,7 +7,7 @@ CurrentModule = MathOptInterface
 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).
 
-## v1.40.0 (May 2, 2025)
+## v1.40.0 (May 4, 2025)
 
 ### Added