Fix PHP 8 introduced breaking change to call_user_func_array()

[Afnisse]

call_user_func_array() is used by HttpClient::getSideload(array $params = []), and since PHP 8^ introduced named arguments, the use of an associative array as arguments, will break the code since the array_merge does not support named arguments.

The fix is changing this line:

zendesk_api_client_php/src/Zendesk/API/HttpClient.php

Line 441 in b451b74

return call_user_func_array('array_merge', $sideloads);

To this:

return call_user_func_array('array_merge', array_values($sideloads));

[schonhoff]

As mentioned in #470 maybe someone can update packagist? This would help a lot! :-)