Add a message Location to represent geo co-ordinates (#48)

Author: tiyash-basu-frequenz

RELEASE_NOTES.md

@@ -10,7 +10,8 @@
 
 ## New Features
 
-<!-- Here goes the main new features and examples or instructions on how to use them -->
+* Added a new message named `Location`, representing the co-ordinates of a
+  geographical location.
 
 ## Bug Fixes
 

proto/frequenz/api/common/location.proto

@@ -0,0 +1,19 @@
+// Geographical co-ordinates of a place.
+//
+// Copyright 2023 Frequenz Energy-as-a-Service GmbH
+//
+// Licensed under the MIT License (the "License");
+// you may not use this file except in compliance with the License.
+
+syntax = "proto3";
+
+package frequenz.api.common.location;
+
+// A pair of geographical co-ordinates, representing the location of a place.
+message Location {
+  // Latitude ranges from -90 (South) to 90 (North)
+  float latitude = 1;
+
+  // Longitude ranges from -180 (West) to 180 (East)
+  float longitude = 2;
+}