Add a deprecated_member() function to fix typing

[llucax]

When using the DeprecatedMember class directly, mypy will struggle because it will think the actual type of the value is DeprecatedMember instead of the real underlying value.

To fix this we create a simple generic wrapper deprecated_member() that will cast the DeprecatedMember to the type of the value.

[Copilot]

Pull Request Overview

This PR introduces a new deprecated_member() function to improve typing when creating deprecated enum members. The function provides a type-safe wrapper around the existing DeprecatedMember class.

• Adds a generic deprecated_member() function that returns the correct type for mypy
• Updates all existing usage of DeprecatedMember to use the new function
• Updates documentation and examples to reflect the new preferred approach

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

File	Description
src/frequenz/core/enum.py	Adds the new deprecated_member() function and updates documentation
tests/test_enum.py	Updates tests to use new function and adds comprehensive test coverage
README.md	Updates example to demonstrate the new function usage
RELEASE_NOTES.md	Documents the new feature and upgrade guidance

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[Marenz]

So will you deprecate direct usage of DeprecatedMember then? 😆

[llucax]

I thought about it. But I think it is too meta 😆

But when we go for 2.0.0 I think I would make it private, we really don't need to expose it at all.

[llucax]

Ahhh, so nice to have gotten issue number 100 for:

• Breaking changes for 2.0 #100

[daniel-zullo-frequenz]

I have a comment to check for. And LGTM

[llucax]

Updated.