docs(changelog): add FastAPI uninstrument memory leak fix with PR references (open-telemetry#3683)

Author: artemziborev

CHANGELOG.md

@@ -13,6 +13,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- `opentelemetry-instrumentation-fastapi`: Fix memory leak in `uninstrument_app()` by properly removing apps from the tracking set
+  ([#XXXX](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/XXXX), [#3683](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3683))
+
 - `opentelemetry-instrumentation-fastapi`: fix wrapping of middlewares
   ([#3012](https://github.com/open-telemetry/opentelemetry-python-contrib/pull/3012))
 - `opentelemetry-instrumentation-falcon`: proper bucket boundaries in stable semconv http duration