Issue #633/#711 add changelog entry

Author: soxofaan

CHANGELOG.md

@@ -16,6 +16,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Improved tracking of metadata changes with `resample_spatial` and `resample_cube_spatial` ([#690](https://github.com/Open-EO/openeo-python-client/issues/690))
 - Move `ComparableVersion` to `openeo.utils.version` (related to [#611](https://github.com/Open-EO/openeo-python-client/issues/611))
 - Deprecate `openeo.rest.rest_capabilities.RESTCapabilities` and introduce replacement `openeo.rest.capabilities.OpenEoCapabilities` ([#611](https://github.com/Open-EO/openeo-python-client/issues/611), [#610](https://github.com/Open-EO/openeo-python-client/issues/610))
+- `MultiBackendJobManager`: start new jobs before downloading the results of finished jobs to use time more efficiently ([#633](https://github.com/Open-EO/openeo-python-client/issues/633))
 
 ### Removed