Clear release notes (#1198)

Author: shsms

RELEASE_NOTES.md

@@ -1,10 +1,17 @@
 # Frequenz Python SDK Release Notes
 
+## Summary
+
+<!-- Here goes a general summary of what this release is about -->
+
 ## Upgrading
 
-- The `microgrid.new_*_pool` methods no longer accept a `set_operating_point` parameter.
-- The power manager now uses a new algorithm described [here](https://frequenz-floss.github.io/frequenz-sdk-python/v1.0-dev/user-guide/microgrid-concepts/#frequenz.sdk.microgrid--setting-power).
+<!-- Here goes notes on how to upgrade from previous versions, including deprecations and what they should be replaced with -->
+
+## New Features
+
+<!-- Here goes the main new features and examples or instructions on how to use them -->
 
 ## Bug Fixes
 
-- Fix `MetricFetcher` leaks when a requested metric fetcher already existed.
+<!-- Here goes notable bug fixes that are worth a special mention or explanation -->