the minimal example generated XLSX file has no data

[shencan]

Description

I use office 2016(mac os) Excel open the minimal example code generated XLSX file. but There's no data

Steps to reproduce the issue:

1. copy the minimal example code
2. run the program

package main

import (
    "fmt"

    "github.com/360EntSecGroup-Skylar/excelize"
)

func main() {
    xlsx := excelize.NewFile()
    // Create a new sheet.
    index := xlsx.NewSheet("Sheet2")
    // Set value of a cell.
    xlsx.SetCellValue("Sheet2", "A2", "Hello world.")
    xlsx.SetCellValue("Sheet1", "B2", 100)
    // Set active sheet of the workbook.
    xlsx.SetActiveSheet(index)
    // Save xlsx file by the given path.
    err := xlsx.SaveAs("./Workbook.xlsx")
    if err != nil {
        fmt.Println(err)
    }
}

Describe the results you received:

Describe the results you expected:

Output of go version:

shencan@MacBook:~/Goscript$ go run write_excel.go
shencan@MacBook:~/Goscript$ ls -l  Workbook.xlsx
-rw-r--r--  1 shencan  staff  5028 12 27 14:09 Workbook.xlsx

Environment details (OS, Microsoft Excel™ version, physical, etc.):
mac os office 2016 Excel

[xuri]

Check the Go version you are using. This library needs Go version 1.8 or later. Relate issue #35, #39, #42, #84, #97 and #121.