add changelog

Author: emdneto

CHANGELOG.md

@@ -24,6 +24,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#4637](https://github.com/open-telemetry/opentelemetry-python/pull/4637))
 - Logging API accepts optional `context`; deprecates `trace_id`, `span_id`, `trace_flags`.
   ([#4597](https://github.com/open-telemetry/opentelemetry-python/pull/4597))
+- Relax protobuf version requirement to support v6
+  ([#4620](https://github.com/open-telemetry/opentelemetry-python/pull/4620))
 
 ## Version 1.34.0/0.55b0 (2025-06-04)