vue3 +el-menu实现路由跳转失败
解决办法：
要在 标签中加 router属性<el-menu router>

<el-container style="height: 500px; border: 1px solid #eee">
        <el-aside width="200px" style="background-color: rgb(238, 241, 246)">
          <el-menu router>
            <el-submenu v-for="(item,index) in $router.options.routes" :index="index + '' ">
              <template slot="title"><i class="el-icon-setting"></i>{{item.name}}</template>
              <el-menu-item  v-for="(item2,index2) in item.children" :index="item2.path">{{item2.name}}</el-menu-item>
            </el-submenu>
          </el-menu>
        </el-aside>

        <el-main>
          <router-view></router-view>
        </el-main>
      </el-container>