release notes for spec update

Author: I750911

docs/release-notes/release_notes.md

@@ -8,15 +8,17 @@
 
 ### 🔧 Compatibility Notes
 
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+- `ChatMessage`, as well as new `MultiChatMessage`, are now subtypes of new interface `ChatMessagesInner`. This may cause type inconsistencies in existing codebase. 
 
 ### ✨ New Functionality
 
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+- Orchestration supports images as input in newly introduced `MultiChatMessage`.
+- `MultiChatMessage` also allows for multiple content items (text or image) in one object.
+- Grounding input can be masked with `DPIConfig`.
 
 ### 📈 Improvements
 
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+- Update Orchestration client to version 2412a
 
 ### 🐛 Fixed Issues