router-view The template root requires exactly one element. code example
Example: The template root requires exactly one element.eslint-plugin-vue
Change the code in App.vue from as follows:-
<template>
<section> // add this section tag here
<img alt="Vue logo" src="./assets/logo.png">
<HelloWorld msg="Welcome to Your Vue.js App" />
</section> // end section here
</template>