Deprecation warnings in PHP 8.4

[alexsegura]

This triggers a few deprecation warnings:

Deprecated: Paygreen\Sdk\Core\Client::__construct(): Implicitly marking parameter $logger as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/vendor/paygreen/paygreen-php/lib/PaygreenSdk/Core/Client.php on line 23

Deprecated: Paygreen\Sdk\Payment\V3\Client::__construct(): Implicitly marking parameter $logger as nullable is deprecated, the explicit nullable type must be used instead in /var/www/html/vendor/paygreen/paygreen-php/lib/PaygreenSdk/Payment/V3/Client.php on line 42