chore(main): release 0.4.0

Author: a2a-bot

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## [0.4.0](https://github.com/a2aproject/a2a-python/compare/v0.3.10...v0.4.0) (2025-11-07)
+
+
+### Features
+
+* add metadata to send message request ([#532](https://github.com/a2aproject/a2a-python/issues/532)) ([12b4a1d](https://github.com/a2aproject/a2a-python/commit/12b4a1d565a53794f5b55c8bd1728221c906ed41))
+
 ## [0.3.10](https://github.com/a2aproject/a2a-python/compare/v0.3.9...v0.3.10) (2025-10-21)