Add PHP 8 Support

[flavioafa]

Hello guys!

Any plans to make this library PHP 8 compatible?

[vitormattos]

Yes! The plan:

• Fork
• swap your PHP version to 8
• Run unit tests and check what broken
• fix the broken tests
• Run smoke tests
• Create a new PR with subject "Make this library PHP 8 compatible"

[vitormattos]

Duplicated by #271