chore(main): release 0.2.15

Author: release-please[bot]

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## [0.2.15](https://github.com/a2aproject/a2a-python/compare/v0.2.14...v0.2.15) (2025-07-21)
+
+
+### Bug Fixes
+
+* Add Input Validation for Empty Message Content ([#327](https://github.com/a2aproject/a2a-python/issues/327)) ([5061834](https://github.com/a2aproject/a2a-python/commit/5061834e112a4eb523ac505f9176fc42d86d8178))
+
 ## [0.2.14](https://github.com/a2aproject/a2a-python/compare/v0.2.13...v0.2.14) (2025-07-18)