Add message linking microgrid and sensor IDs (#284)

Author: stefan-brus-frequenz

RELEASE_NOTES.md

@@ -1,5 +1,9 @@
 # Frequenz Common API Release Notes
 
+## New Features
+
+- Added message linking microgrid and sensor IDs.
+
 ## Bug Fixes
 
 - Fix a dependency issue by pinning the `grpcio` version and related libraries.

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

@@ -71,3 +71,12 @@ 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;
+}