docs: update changelog for integrations/llama_stack (#2090)

* Update changelog for integrations/llama_stack

* Update CHANGELOG.md

---------

Co-authored-by: Amnah199 <13835656+Amnah199@users.noreply.github.com>
Co-authored-by: Amna Mubashar <amnahkhan.ak@gmail.com>

Author: HaystackBot

integrations/llama_stack/CHANGELOG.md

@@ -0,0 +1,9 @@
+# Changelog
+
+## [integrations/llama_stack-v1.0.0] - 2025-07-11
+
+### 🚀 Features
+
+- Add llama-stack integration (#2064)
+
+<!-- generated by git-cliff -->