Take exception message from provider response in case of statusCode >= 400

Hey guys.

So I as a developer would like to see message from provider response rather than generic The geocoder server returned an invalid response (%d) for query "%s". We could not parse it. message.

We faced with an issue which is pretty hard to debug on dockerized application. It would be much easier to understand what went wrong if we get message from particular provider response in case InvalidServerResponse is thrown on line: https://github.com/geocoder-php/Geocoder/blob/master/src/Http/Provider/AbstractHttpProvider.php#L78

The main issue that each provider has their own response structure in case of bad request occurs. I don't see a good solution here so far and I have only 2 thoughts so far:

• getParsedResponse method need to be an abstract so each provider will implement their own mechanism of catching errors.
  https://github.com/geocoder-php/Geocoder/blob/master/src/Http/Provider/AbstractHttpProvider.php#L68-L87
• We could add another abstract method like abstract protected function throwClientException(string $message) method inside of an AbstractHttpProvider class. And each provider have to implement it.

I suppose it is kind of feature request.

从 src/Http/Provider/AbstractHttpProvider.php 开始，重点查看 getParsedResponse 以及 68-87 行附近的 InvalidServerResponse 路径。检查各 provider 特有的响应结构有何不同，然后定义一种策略，使状态码 >=400 时显示 provider 的消息，而不是通用错误；当该行为与所选设计保持一致时即完成。