feature: empty body sign handler

Author: yuguo.dtpe

volcenginesdkcore/interceptor/interceptors/sign_request_interceptor.py

@@ -39,7 +39,7 @@ def update_params_for_auth(host, path, method, headers, querys, auth_settings, b
 
         for auth in auth_settings:
             headers["Host"] = host
-            if method in ["POST", "PUT", "DELETE", "PATCH"]:
+            if method in ["POST", "PUT", "DELETE", "PATCH"] and body is not None:
                 body = json.dumps(body)
             else:
                 body = ""