docs: Add CHANGELOG entry for structured outputs instrumentation

Author: Nik-Reddy

CHANGELOG.md

@@ -13,6 +13,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Added
 
+- `opentelemetry-instrumentation-openai-v2`: Add instrumentation for `chat.completions.parse()` structured outputs
+  ([#4416](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4416))
 - Bump `pylint` to `4.0.5`
   ([#4244](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/4244))