Auto-generate CHANGELOG.md

[ricardoboss]

Something like this: https://mokkapps.de/blog/how-to-automatically-generate-a-helpful-changelog-from-your-git-commit-messages/

but for PHP. Using:

• https://github.com/BrainMaestro/composer-git-hooks
• https://github.com/marcocesarato/php-conventional-changelog