Add message linking microgrid and sensor IDs (#283)

Author: stefan-brus-frequenz

RELEASE_NOTES.md

@@ -10,7 +10,7 @@
 
 ## New Features
 
-<!-- Here goes the main new features and examples or instructions on how to use them -->
+- Added message linking microgrid and sensor IDs.
 
 ## Bug Fixes
 

proto/frequenz/api/common/v1/microgrid/microgrid.proto

@@ -77,3 +77,12 @@ message MicrogridComponentIDs {
   // List of component IDs belonging to this microgrid.
   repeated uint64 component_ids = 2;
 }
+
+/// A message to link sensor IDs with their respective microgrid ID.
+message MicrogridSensorIDs {
+  // The ID of the microgrid.
+  uint64 microgrid_id = 1;
+
+  // List of sensor IDs belonging to this microgrid.
+  repeated uint64 sensor_ids = 2;
+}