Clear release notes

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

RELEASE_NOTES.md

@@ -1,19 +1,17 @@
 # Frequenz channels Release Notes
 
-## New Features
+## Summary
+
+<!-- Here goes a general summary of what this release is about -->
 
-- There is a new `Receiver.triggered` method that can be used instead of `selected_from`:
+## Upgrading
 
-  ```python
-  async for selected in select(recv1, recv2):
-      if recv1.triggered(selected):
-          print('Received from recv1:', selected.message)
-      if recv2.triggered(selected):
-          print('Received from recv2:', selected.message)
-  ```
+<!-- Here goes notes on how to upgrade from previous versions, including deprecations and what they should be replaced with -->
+
+## New Features
 
-* `Receiver.filter()` can now properly handle `TypeGuard`s. The resulting receiver will now have the narrowed type when a `TypeGuard` is used.
+<!-- Here goes the main new features and examples or instructions on how to use them -->
 
 ## Bug Fixes
 
-- Fixed a memory leak in the timer.
+<!-- Here goes notable bug fixes that are worth a special mention or explanation -->