降低对象旋转速度

Question

这是我用鼠标旋转的对象的代码，但我想将其减慢到每秒18°。
这是关于二维自上而下的坦克游戏。

private Vector3 mouse_pos;
public Transform target;
private Vector3 object_pos;
private float angle;

private void Start()
{
   

}

void Update()
{
    mouse_pos = Input.mousePosition;
    mouse_pos.z = -20;
    object_pos = Camera.main.WorldToScreenPoint(target.position);
    mouse_pos.x = mouse_pos.x - object_pos.x;
    mouse_pos.y = mouse_pos.y - object_pos.y;
    angle = Mathf.Atan2(mouse_pos.y, mouse_pos.x) * Mathf.Rad2Deg;
    transform.rotation = Quaternion.Euler(0, 0, angle - 90);
    
}