Update CHANGELOG.md

Author: asasvari

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- Running mypy on SDK resources
+  ([#4053](https://github.com/open-telemetry/opentelemetry-python/pull/4053))
 - Standardizing timeout calculation in measurement consumer collect to nanoseconds
   ([#4074](https://github.com/open-telemetry/opentelemetry-python/pull/4074))
 - optional scope attributes for logger creation