chore(main): release 0.2.1 (#666)

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


## [0.2.1](v0.2.0...v0.2.1)
(2025-05-27)


### Features

* Add a new boolean for supporting authenticated extended cards
([#618](#618))
([e0a3070](e0a3070))
* Add optional referenceTaskIds for task followups
([#608](#608))
([5368e77](5368e77))

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

---------

Co-authored-by: release-please[bot] <55107282+release-please[bot]@users.noreply.github.com>
Co-authored-by: Holt Skinner <holtskinner@google.com>

Author: release-please[bot]

.github/actions/spelling/excludes.txt

@@ -89,3 +89,4 @@
 \.vscode/
 ^\Qdocs/partners.md\E$
 ^\Qspecification/json/a2a.json\E$
+CHANGELOG.md

CHANGELOG.md

@@ -0,0 +1,8 @@
+# Changelog
+
+## [0.2.1](https://github.com/google/A2A/compare/v0.2.0...v0.2.1) (2025-05-27)
+
+### Features
+
+* Add a new boolean for supporting authenticated extended cards ([#618](https://github.com/google/A2A/issues/618)) ([e0a3070](https://github.com/google/A2A/commit/e0a3070fc289110d43faf2e91b4ffe3c29ef81da))
+* Add optional referenceTaskIds for task followups ([#608](https://github.com/google/A2A/issues/608)) ([5368e77](https://github.com/google/A2A/commit/5368e7728cb523caf1a9218fda0b1646325f524b))