Make rawCall method protected instead of private

There is no point keeping the rawCall method private. On the other hand, the rawCall method being protected makes it easier to extend \Ovh\Api class.

Use case : I extend \Ovh\Api class and want to override get, post, put and delete methods to manipulate $content param before making a request. I cannot do this now because i cannot call private rawCall method from a child class. I can provide a quick explanation snippet if needed.

src/Api.php

@@ -223,7 +223,7 @@ class Api
      * @return array
      * @throws \GuzzleHttp\Exception\ClientException if http request is an error
      */
-    private function rawCall($method, $path, $content = null, $is_authenticated = true, $headers = null)
+    protected function rawCall($method, $path, $content = null, $is_authenticated = true, $headers = null)
     {
         $url     = $this->endpoint . $path;
         $request = new Request($method, $url);