added changelog entry

Author: ItayGibel-helios

CHANGELOG.md

@@ -7,6 +7,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased](https://github.com/open-telemetry/opentelemetry-python/compare/v1.5.0-0.24b0...HEAD)
 
+### Changed
+
+- `opentelemetry-instrumentation-urllib3` Added `_ExtendedRequestHookT` as an optional type of `request_hook`.
+   this type extends the existing `_RequestHookT` with two more fields - the request body and the request headers
+
 ## [1.5.0-0.24b0](https://github.com/open-telemetry/opentelemetry-python/releases/tag/v1.5.0-0.24b0) - 2021-08-26
 
 ### Added