Fix "Uncaught Error: Call to a member function getStatusCode() on null" (#203)
Fix "Uncaught Error: Call to a member function getStatusCode() on null" (#203)

The method "MessageSentReport::getStatusCode" now considers that its
"response" property can be null (because Guzzle can return null when
calling "RequestException::getResponse").
Minishlink/web-push,web-push-libs/web-push-php