Clear release notes

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

Author: llucax

RELEASE_NOTES.md

@@ -1,21 +1,17 @@
 # Frequenz Core Library Release Notes
 
-## New Features
+## Summary
+
+<!-- Here goes a general summary of what this release is about -->
 
-- A new `frequenz.core.enum` module was added, providing a drop-in replacement `Enum` that supports deprecating members.
+## Upgrading
 
-   Example:
+<!-- Here goes notes on how to upgrade from previous versions, including deprecations and what they should be replaced with -->
+
+## New Features
 
-   ```python
-   from frequenz.core.enum import Enum, DeprecatedMember
+<!-- Here goes the main new features and examples or instructions on how to use them -->
 
-   class TaskStatus(Enum):
-       OPEN = 1
-       IN_PROGRESS = 2
-       PENDING = DeprecatedMember(1, "PENDING is deprecated, use OPEN instead")
-       DONE = DeprecatedMember(3, "DONE is deprecated, use FINISHED instead")
-       FINISHED = 4
+## Bug Fixes
 
-   status1 = TaskStatus.PENDING  # Warns: "PENDING is deprecated, use OPEN instead"
-   assert status1 is TaskStatus.OPEN
-   ```
+<!-- Here goes notable bug fixes that are worth a special mention or explanation -->