New standard of Vietnamese has been released

[luong-komorebi]

Reference : https://tuoitre.vn/pgs-ts-bui-hien-cong-bo-phan-2-phuong-an-cai-tien-chu-tieng-viet-20171226122603329.htm

Due to this latest release of Vietnamese modern standard, I think it's high time we change our code to support it.