Record the swagger-core 2.2.54 upgrade in the changelog

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: bnasslahsen

CHANGELOG.md

@@ -23,7 +23,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - **The Scalar starters no longer register forwarded-header handling.** Set `server.forward-headers-strategy=framework` (or `native`) behind a trusted proxy
 - Add `springdoc.cache.max-entries` (default `100`) to bound the per-locale OpenAPI cache
 - Document the security policy and the release versioning scheme
-- Upgrade swagger-core to version **2.2.53**
+- #3351 – `java.time.Duration`, `LocalTime` and `OffsetTime` are now resolved by swagger-core instead of being forced to a bare `string`, so they carry a `format` (`duration` and `partial-time` respectively for the first two)
+- Upgrade swagger-core to version **2.2.54**
 - Upgrade swagger-ui to version **5.32.14**
 
 ### Fixed