Compatibility with PHP 8.0

Hi,

Thanks for writing this great plugin.

Just here to report some error from PHP 8.0.

https://www.example.com/:

Notice: spl_autoload_register(): Argument #2 ($do_throw) has been ignored, spl_autoload_register() will always throw in /var/www/html/wp-content/plugins/invisible-recaptcha/includes/MchLibAutoloader.php on line 53

Notice: spl_autoload_register(): Argument #2 ($do_throw) has been ignored, spl_autoload_register() will always throw in /var/www/html/wp-content/plugins/invisible-recaptcha/engine/RequestHandler.php on line 84

Notice: spl_autoload_register(): Argument #2 ($do_throw) has been ignored, spl_autoload_register() will always throw in /var/www/html/wp-content/plugins/invisible-recaptcha/engine/Controllers/ModulesController.php on line 104

https://www.example.com/login.php (after submitted):

Notice: spl_autoload_register(): Argument #2 ($do_throw) has been ignored, spl_autoload_register() will always throw in /var/www/html/wp-content/plugins/invisible-recaptcha/includes/MchLibAutoloader.php on line 53

Notice: spl_autoload_register(): Argument #2 ($do_throw) has been ignored, spl_autoload_register() will always throw in /var/www/html/wp-content/plugins/invisible-recaptcha/engine/RequestHandler.php on line 84

Notice: spl_autoload_register(): Argument #2 ($do_throw) has been ignored, spl_autoload_register() will always throw in /var/www/html/wp-content/plugins/invisible-recaptcha/engine/Controllers/ModulesController.php on line 104

Fatal error: Array and string offset access syntax with curly braces is no longer supported in /var/www/html/wp-content/plugins/invisible-recaptcha/includes/utils/MchIPUtils.php on line 197

Wish you happiness.