chore(main): release 0.3.8 (#481)

🤖 I have created a release *beep* *boop*
---


##
[0.3.8](v0.3.7...v0.3.8)
(2025-10-06)


### Bug Fixes

* Add `__str__` and `__repr__` methods to `ServerError`
([#489](#489))
([2c152c0](2c152c0))
* **grpc:** Fix missing extensions from protobuf
([#476](#476))
([8dbc78a](8dbc78a))
* **rest:** send `historyLength=0` (avoid falsy omission)
([#480](#480))
([ed28b59](ed28b59)),
closes [#479](#479)


### Documentation

* `a2a-sdk[all]` installation command in Readme
([#485](#485))
([6ac9a7c](6ac9a7c))

---
This PR was generated with [Release
Please](https://github.com/googleapis/release-please). See
[documentation](https://github.com/googleapis/release-please#release-please).

Author: a2a-bot

CHANGELOG.md

@@ -1,5 +1,19 @@
 # Changelog
 
+## [0.3.8](https://github.com/a2aproject/a2a-python/compare/v0.3.7...v0.3.8) (2025-10-06)
+
+
+### Bug Fixes
+
+* Add `__str__` and `__repr__` methods to `ServerError` ([#489](https://github.com/a2aproject/a2a-python/issues/489)) ([2c152c0](https://github.com/a2aproject/a2a-python/commit/2c152c0e636db828839dc3133756c558ab090c1a))
+* **grpc:** Fix missing extensions from protobuf ([#476](https://github.com/a2aproject/a2a-python/issues/476)) ([8dbc78a](https://github.com/a2aproject/a2a-python/commit/8dbc78a7a6d2036b0400873b50cfc95a59bdb192))
+* **rest:** send `historyLength=0` (avoid falsy omission) ([#480](https://github.com/a2aproject/a2a-python/issues/480)) ([ed28b59](https://github.com/a2aproject/a2a-python/commit/ed28b5922877c1c8386fd0a7e05471581905bc59)), closes [#479](https://github.com/a2aproject/a2a-python/issues/479)
+
+
+### Documentation
+
+* `a2a-sdk[all]` installation command in Readme ([#485](https://github.com/a2aproject/a2a-python/issues/485)) ([6ac9a7c](https://github.com/a2aproject/a2a-python/commit/6ac9a7ceb6aff1ca2f756cf75f58e169b8dcd43a))
+
 ## [0.3.7](https://github.com/a2aproject/a2a-python/compare/v0.3.6...v0.3.7) (2025-09-22)