Add a changelog entry

Author: kjagiello

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- Removed superfluous py.typed markers and added them where they were missing
+  ([#4172](https://github.com/open-telemetry/opentelemetry-python/pull/4172))
+
 ## Version 1.27.0/0.48b0 (2024-08-28)
 
 - Implementation of Events API