Changelog entry

Signed-off-by: Sasha Bogicevic <[email protected]>

Author: v0d1ch

CHANGELOG.md

@@ -8,6 +8,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 As a minor extension, we also keep a semantic version for the `UNRELEASED`
 changes.
 
+## [0.23.0] - UNRELEASED
+
+- Hydra API server responds with the correct `Content-Type` header `application-json`.
+
 ## [0.22.1] - 2025.06.27
 
 * Fix for bug where node got stalled at `ReplayingState` [#2089](https://github.com/cardano-scaling/hydra/issues/2089)