Start new development cycle

Author: hynek

CHANGELOG.md

@@ -13,6 +13,9 @@ You can find our backwards-compatibility policy [here](https://github.com/hynek/
 <!-- changelog follows -->
 
 
+## [Unreleased](https://github.com/hynek/structlog/compare/25.4.0...HEAD)
+
+
 ## [25.4.0](https://github.com/hynek/structlog/compare/25.3.0...25.4.0) - 2025-06-02
 
 ### Added