Removed Carbon dependency

• Removed the Carbon dependency.
• Check compatibility with PHP 7.2

Added compatibility with Laravel 5.8 (Polyfill to Carbon 2)

Added polyfill to isBefore of Carbon 2

Signed-off-by: victor <[email protected]>

1.0.0: Set validation composite package as Suggested package

This version is compatible with Laravel >= 5. I achieved this added the illuminatech/validation-composite as suggested package.