[BUG]Issue with the nacos registry in web.NewService()

[zhang-jianqiang]

That reports an error when I use nacos registry in web.NewService():
panic: assignment to entry in nil map
My code:

package main

import (
	"user/config/config"
	"go-micro.dev/v4/web"
)

var (
	service = "go-layout"
	version = "latest"
)

func main() {
	srv := web.NewService(
		web.Name(service),
		web.Version(version),
		web.Registry(config.NewRegistry()),
		// web.Metadata(map[string]string{"version": version}),
	)
	srv.Run()
}

package config

import (
	"github.com/asim/go-micro/plugins/registry/nacos/v4"
	"github.com/nacos-group/nacos-sdk-go/v2/common/constant"
	"go-micro.dev/v4/registry"
)

func NewRegistry() registry.Registry {
	DefaultClientConfig := constant.ClientConfig{
		NamespaceId: "45d1be27-88ab-487d-b0ba-c09557fcaf29",
	}
	r := nacos.NewRegistry(
		nacos.WithClientConfig(DefaultClientConfig),
		nacos.WithAddress([]string{
			"127.0.0.1:8848",
		}))
	return r
}

go.mod

module user

go 1.18

require (
	github.com/asim/go-micro/plugins/registry/nacos/v4 v4.0.0-20220404185419-6dedee5d8c2c
	github.com/nacos-group/nacos-sdk-go/v2 v2.0.1
	go-micro.dev/v4 v4.2.1
)

Debug code,I find it will be ok to add web.Metadat option in web.NewService().

Environment:
Go Version: go version go1.18 windows/amd64