Clear release notes (#1201)

Author: shsms

RELEASE_NOTES.md

@@ -1,6 +1,17 @@
 # Frequenz Python SDK Release Notes
 
-## Bug Fixes
+## Summary
+
+<!-- Here goes a general summary of what this release is about -->
+
+## Upgrading
+
+<!-- Here goes notes on how to upgrade from previous versions, including deprecations and what they should be replaced with -->
 
-- Fixes a bug where battery pool metrics would stop for one actor when another actor managing the same components stops its pool.
+## New Features
+
+<!-- Here goes the main new features and examples or instructions on how to use them -->
+
+## Bug Fixes
 
+<!-- Here goes notable bug fixes that are worth a special mention or explanation -->