public PayloadBuilder urlArgs(final String... urlArgs){
        aps.put("url-args", urlArgs);
        return this;
    }
Sets the "url-args" key that are paired with the placeholders
inside the urlFormatString value of your website.json file.
The order of the placeholders in the URL format string determines
the order of the values supplied by the url-args array.

@param urlArgs the values to be paired with the placeholders inside
               the urlFormatString value of your website.json file.
@return  this
src/main/java/com/notnoop/apns/PayloadBuilder.java