Some of Guzzle methods are deprecated

Some of Guzzle methods like:
``` php
    GuzzleHttp\Psr7\parse_request();
```
which used in **'HttpRequestParser'** class in **parse** method and
``` php
    GuzzleHttp\Psr7\str();
```
which used in **'CloseResponseTrait'**  **close** method are deprecated and new methods should be replaced.