func (WebpPlugin) preProcess(obj *object.FileObject, req *http.Request) {
	if strings.Contains(req.Header.Get("Accept"), "image/webp") && obj.HasTransform() {
		obj.Transforms.Format("webp")
		obj.UpdateKey("webp")
	}
}
PreProcess add webp transform to object
package plugins
import (
	"net/http"
	"strings"
	"github.com/aldor007/mort/pkg/object"
	"github.com/aldor007/mort/pkg/response"
)
func init() {
	RegisterPlugin("webp", WebpPlugin{})
}
type WebpPlugin struct {
}
func (WebpPlugin) configure(_ interface{}) {
}