SDK is not compatible with PHP 8.0

[GeeH]

Detailed description

Bug: Composer require states that the package is incompaitble with your PHP version if you're running PHP 8.0

Context

Would be beneficial to be able to use the library with PHP 8.0 and newer.

Possible implementation

Update composer.json to include ^8.0 | ^7.2 - check automated tests pass under PHP 8.0

Your environment

PHP 8.0.2, MacOS