update changelog

Author: dbarker

CHANGELOG.md

@@ -6,6 +6,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## Unreleased
+- Fix OTLP encoders missing instrumentation scope schema url and attributes
+  ([#4359](https://github.com/open-telemetry/opentelemetry-python/pull/4359))  
 
 ## Version 1.29.0/0.50b0 (2024-12-11)