PR #839 Add changelog entry

ref eu-cdse/openeo-cdse-infra#859

Author: soxofaan

CHANGELOG.md

@@ -11,6 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - `MultiBackendJobManager`: add `download_results` option to enable/disable the automated download of job results once completed by the job manager ([#744](https://github.com/Open-EO/openeo-python-client/issues/744))
 - Support UDF based spatial and temporal extents in `load_collection`, `load_stac` and `filter_temporal` ([#831](https://github.com/Open-EO/openeo-python-client/pull/831))
+- `MultiBackendJobManager`: keep number of "queued" jobs below 10 for better CDSE compatibility (eu-cdse/openeo-cdse-infra#859)
 
 ### Changed