[Unity] RectTransform 내 피벗 Top과 Bottom 설정

rectTransform = RectTransform 변수 > 
GetComponent<RectTransform>() 또는 GetComponent<Transform> as RectTransform 가능

top = 상단 값
bottom = 하단값

rectTransform.offsetMin = new Vector2(rectTransform.offsetMin.x, bottom);
rectTransform.offsetMax = new Vector2(rectTransform.offsetMax.x, top);