code: public static byte[] sha256(String data, String charset) {
  		return new Digester(DigestAlgorithm.SHA256).digest(data, charset);
  	}
docs: 计算SHA-256摘要值
  
  @param data 被摘要数据
  @param charset 编码
  @return SHA-256摘要
  @since 3.0.8