message: docs: document request_timeout in version_history
  This commit documents the proto change in
diff: @@ -48,6 +48,7 @@ Version history
  :ref:`use_data_plane_proto<envoy_api_field_config.ratelimit.v2.RateLimitServiceConfig.use_data_plane_proto>`
  boolean flag in the ratelimit configuration.
  Support for the legacy proto :repo:`source/common/ratelimit/ratelimit.proto` is deprecated and will be removed at the start of the 1.9.0 release cycle.
  +* rest-api: added ability to set the :ref:`request timeout <envoy_api_field_core.ApiConfigSource.request_timeout>` for REST API requests.
  * router: added ability to set request/response headers at the :ref:`envoy_api_msg_route.Route` level.
  * tracing: added support for configuration of :ref:`tracing sampling
  <envoy_api_field_config.filter.network.http_connection_manager.v2.HttpConnectionManager.tracing>`.
  