Add CHANGELOG entry.

Author: tylerbenson

CHANGELOG.md

@@ -18,6 +18,8 @@ release.
 ### Resource
 
 ### Semantic Conventions
+- Move X-Ray Env Variable propagation to span link instead of parent for AWS Lambda.
+  ([#3166](https://github.com/open-telemetry/opentelemetry-specification/pull/3166))
 
 ### Compatibility