Update release notes

Signed-off-by: Sahas Subramanian <[email protected]>

Author: shsms

RELEASE_NOTES.md

@@ -1,17 +1,5 @@
 # Frequenz Microgrid Component Graph Library Release Notes
 
-## 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 -->
-
 ## 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 -->
+- It is now possible to create subclasses of the `ComponentGraph` and `ComponentGraphConfig` classes from python.