Improve CHANGELOG.md format

[EchoEllet]

Is there an existing issue for this?

• I have searched the existing issues

Use case

The CHANGELOG.md is getting bigger and we do automate the process of generating release notes, it might not be very clear what's added, removed, or changed.

Having a readable CHANGELOG.md while still automating the process of generating release notes for each release
require to enforce the use of conventional commits in the PR title and using Keep a Changelog

Proposal

I do suggest that we:

• Update the format ofCHANGELOG.md to apply to Keep a Changelog first by automating this task.
• Add a new check in the main GitHub workflow to check if the title confirms conventional commits.
• When publishing a new version, extract and generate the changes in a new version by using a tool that gets them from the PRs titles and integrates with Keep a Changelog format and Conventional Commits
  , we can use GitHub action (e.g. extract-release-notes, changelog-version-extractor) or dart package (for dev only) such as change.
• To allow adding notes, the workflow will get the notes of the GitHub release created by the maintainer manually and put them at the top and will be optional, the changes will be automated

The GitHub generate release notes button will be no longer required as it doesn't use a specific format and it's what we have been using for automating the changes.