Update changelog for version 1.2.8 (#196)

Author: Ayush0054

changelog/overview.mdx

@@ -3,6 +3,19 @@ title: "Product updates"
 mode: "wide"
 ---
 
+<Update label="2025-04-04" description="v1.2.8">
+## 1.2.8
+
+# Changelog
+
+## New Features:
+
+- **Toolkit Instructions**: Extended `Toolkit` with `instructions` and `add_instructions` to enable you to specify additional instructions related to how a tool should be used. These instructions are then added to the model’s “system message” if `add_instructions=True` .
+
+## Bug Fixes:
+
+- **Teams transfer functions**: Some tool definitions of teams failed for certain models. This has been fixed.
+</Update>
 <Update label="2025-04-02" description="v1.2.7">
 ## 1.2.7