官方客户端支持 go mod形式
### demo
```
package main
import (
"fmt"
"github.com/go-zk/zk"
"time"
)
func main() {
c, _, err := zk.Connect([]string{"127.0.0.1"}, time.Second) //*10)
if err != nil {
panic(err)
}
children, stat, ch, err := c.ChildrenW("/")
if err != nil {
panic(err)
}
fmt.Printf("%+v %+v\n", children, stat)
e := <-ch
fmt.Printf("%+v\n", e)
}
```