fix(flow): 解决SwitchAction缺头文件的问题

Author: hevake

modules/flow/actions/switch_action.cpp

@@ -19,6 +19,8 @@
  */
 #include "switch_action.h"
 
+#include <sstream>
+
 #include <tbox/base/assert.h>
 #include <tbox/base/defines.h>
 #include <tbox/base/json.hpp>