Add Python 3.11 support to RELEASE_NOTES

Signed-off-by: Leandro Lucarella <leandro.lucarella@frequenz.com>

Author: llucax

RELEASE_NOTES.md

@@ -47,7 +47,7 @@ time.
 
 ## New Features
 
-<!-- Here goes the main new features and examples or instructions on how to use them -->
+* Python 3.11 is now supported!
 
 ## Bug Fixes