Client Bugfix: Actually update the payload

Signed-off-by: Mathias L. Baumann <[email protected]>

Author: Marenz

RELEASE_NOTES.md

@@ -14,4 +14,4 @@
 
 ## Bug Fixes
 
-<!-- Here goes notable bug fixes that are worth a special mention or explanation -->
+* Fixed that client.update() was ignoring updates to "payload".

src/frequenz/client/dispatch/_client.py

@@ -211,6 +211,8 @@ async def update(
                     msg.update.selector.CopyFrom(component_selector_to_protobuf(val))
                 case "is_active":
                     msg.update.is_active = val
+                case "payload":
+                    msg.update.payload.update(val)
                 case "active":
                     msg.update.is_active = val
                     key = "is_active"