docs: update changelog for integrations/mcp (#1848)

* Update changelog for integrations/mcp

* Update CHANGELOG.md

---------

Co-authored-by: anakin87 <[email protected]>
Co-authored-by: Stefano Fiorucci <[email protected]>

Author: HaystackBot

integrations/mcp/CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## [integrations/mcp-v0.3.1] - 2025-05-28
+
+### 🌀 Miscellaneous
+
+- App pins for MCP (#1845)
+
 ## [integrations/mcp-v0.3.0] - 2025-05-27
 
 ### 🚀 Features