feat(v2client): inject X-Request-ID in headers if REQUEST_ID in env

If REQUEST_ID is set in the system env, then all v2 API calls will
have X-Request-ID header set to the value of REQUEST_ID. This is
particularly helpful in debugging.

riocli/v2client/client.py

@@ -50,6 +50,10 @@ def _get_auth_header(self: Client, with_project: bool = True) -> dict:
         if with_project and self._project is not None:
             headers['project'] = self._project
 
+        custom_client_request_id = os.getenv('REQUEST_ID')
+        if custom_client_request_id:
+            headers['X-Request-ID'] = custom_client_request_id
+
         return headers
 
     # Project APIs