二维簇状柱形图

例如，创建如下效果的二维簇状柱形图：

package main
import (
    "fmt"
    "github.com/360EntSecGroup-Skylar/excelize"
)
func main() {
    categories := map[string]string{"A2": "Small", "A3": "Normal", "A4": "Large", "B1": "Apple", "C1": "Orange", "D1": "Pear"}
    values := map[string]int{"B2": 2, "C2": 3, "D2": 3, "B3": 5, "C3": 2, "D3": 4, "B4": 6, "C4": 7, "D4": 8}
    f := excelize.NewFile()
    for k, v := range categories {
        f.SetCellValue("Sheet1", k, v)
    }
    for k, v := range values {
        f.SetCellValue("Sheet1", k, v)
    }
    err := f.AddChart("Sheet1", "E1", `{"type":"col","series":[{"name":"Sheet1!$A$2","categories":"","values":"Sheet1!$B$2:$D$2"},{"name":"Sheet1!$A$3","categories":"Sheet1!$B$1:$D$1","values":"Sheet1!$B$3:$D$3"},{"name":"Sheet1!$A$4","categories":"Sheet1!$B$1:$D$1","values":"Sheet1!$B$4:$D$4"}],"format":{"x_scale":1.0,"y_scale":1.0,"x_offset":15,"y_offset":10,"print_obj":true,"lock_aspect_ratio":false,"locked":false},"legend":{"position":"left","show_legend_key":false},"title":{"name":"Fruit 2D Column Chart"},"plotarea":{"show_bubble_size":true,"show_cat_name":false,"show_leader_lines":false,"show_percent":true,"show_series_name":true,"show_val":true},"show_blanks_as":"zero"}`)
    if err != nil {
        fmt.Println(err)
    }
    // 保存工作簿
    err = f.SaveAs("./Book1.xlsx")
    if err != nil {
        fmt.Println(err)
    }
}