Add changelog

Author: xrmx

CHANGELOG.md

@@ -12,6 +12,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- opentelemetry-sdk: make it possible to override the default processors in the SDK configurator
+  ([#4806](https://github.com/open-telemetry/opentelemetry-python/pull/4806))
 - docs: Added sqlcommenter example
   ([#4734](https://github.com/open-telemetry/opentelemetry-python/pull/4734))
 - build: bump ruff to 0.14.1