Update CHANGELOG.md

Author: Kludex

CHANGELOG.md

@@ -17,8 +17,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   ([#3100](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3100))
 - Add support to database stability opt-in in `_semconv` utilities and add tests
   ([#3111](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3111))
-- `opentelemetry-opentelemetry-pymongo` Add `py.typed` file to enable PEP 561
-  ([#3137](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3137))
 
 ### Fixed