设置请求header
```
package main
import (
"github.com/PeterYangs/article-spider/fileTypes"
"github.com/PeterYangs/article-spider/form"
"github.com/PeterYangs/article-spider/spider"
)
func main() {
f := form.Form{
Host: "https://www.doyo.cn",
Channel: "/game/2-1-[PAGE].html",
Limit: 5,
PageStart: 1,
ListSelector: "body > div.mobile_game_wrap.w1168.clearfix.bg > div > div > div.tab_box > div > div > ul > li",
ListHrefSelector: " div > a:nth-child(1)",
DetailFields: map[string]form.Field{
"content": {Types: fileTypes.HtmlWithImage, Selector: "#hiddenDetail > div", ExcelHeader: "C"},
},
DetailMaxCoroutine: 5,
HttpHeader: map[string]string{"User-Agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/89.0.4389.90 Safari/537.36"},
}
spider.Start(f)
}
```
**HttpHeader**,类型为**map[string]string**
