Update release notes

Signed-off-by: Simon Völcker <simon.voelcker@frequenz.com>

Author: simonvoelcker

RELEASE_NOTES.md

@@ -13,6 +13,9 @@
 - The microgrid client now tolerates the API server being absent or returning incomplete data at startup. `MicrogridClientHandle::try_new` establishes the gRPC connection lazily, so it succeeds regardless of whether the server is reachable; transient stream errors are then handled by the existing per-stream retry loop. `LogicalMeterHandle::try_new` (and therefore `Microgrid::try_new`) wraps the entire component-graph setup — listing components, listing connections, and building the graph — in a single retry loop that sleeps 3 seconds between attempts, so applications block waiting for the server and a valid graph instead of exiting with an error.
 
 - `Bounds::combine_parallel`, `Bounds::intersect`, and `Bounds::merge_if_overlapping` are now public, allowing external callers to combine bounds without going through higher-level types.
+- Put test utils under a feature gate.
+- Added `MockMicrogridApiClient::augment_electrical_component_bounds`: It captures requests so that these can be used in test cases. Obtain the list of captured requests using `MockMicrogridApiClient::augment_bounds_calls_handle` (also new).
+- Added `MockComponent.add_component_bounds`: It allows to add metric bounds to a mock component.
 
 ## Bug Fixes