Laravel＋Vueで error 'Vue' is not defined が出てしまう

Laravel＋Vue環境で eslintを入れているのですが、eslint実行時に

error 'Vue' is not defined

が出てしまいます。（ターミナルにエラーは出るものの、Vueファイルのコンパイル自体はできる）
原因がわからないので、教えていただけると幸いです。
各種ファイルの設定以下の通りです。

app.js

js
/**
 * First we will load all of this project's JavaScript dependencies which
 * includes Vue and other libraries. It is a great starting point when
 * building robust, powerful web applications using Vue and Laravel.
 */

require('./bootstrap');

window.Vue = require('vue');

/**
 * The following block of code may be used to automatically register your
 * Vue components. It will recursively scan this directory for the Vue
 * components and automatically register them with their "basename".
 *
 * Eg. ./components/ExampleComponent.vue -> <example-component></example-component>
 */

// const files = require.context('./', true, /.vue$/i)
// files.keys().map(key => Vue.component(key.split('/').pop().split('.')[0], files(key).default))

Vue.component('example-component', require('./components/ExampleComponent.vue').default);

/**
 * Next, we will create a fresh Vue application instance and attach it to
 * the page. Then, you may begin adding components to this application
 * or customize the JavaScript scaffolding to fit your unique needs.
 */

const app = new Vue({
    el: '#app',
});

ExampleComponent.vue

<template>
    <div class="container">
        <div class="row justify-content-center">
            <div class="col-md-8">
                <div class="card">
                    <div class="card-header">Example Component</div>

                    <div class="card-body">
                        I'm an example component.
                    </div>
                </div>
            </div>
        </div>
    </div>
</template>

<script>
    export default {
        mounted() {
            console.log('Component mounted.')
        }
    }
</script>

eslintrc.js

let rules = {
    "no-unused-vars": ["warn", { vars: "local", args: "none" }],
    "no-undef": "warn",
    "no-redeclare": "warn",
    "no-debugger": "warn",
    "no-console": "warn",
    "no-empty": "warn"
};
if (process.env.NODE_ENV == "production") {
    rules["no-debugger"] = "error";
    rules["no-console"] = "error";
}

module.exports = {
    plugins: [
      "vue"  
    ],
    extends: [
        "eslint:recommended",
        "plugin:vue/essential",
        'plugin:vue/recommended'// vue.js使ってなくてもlaravel-mix-eslintの仕様上必要
    ],
    env: {
        browser: true,
        es6: true,
        amd: true,
        jquery: true
    },
    parserOptions: {
        parser: 'babel-eslint',
        ecmaVersion: "2018"
    },
    rules: {
        "quotes": ["warn", "single"] 
    },
    globals:[
       "Vue: true"
    ]    
};

webpack.mix.js

js
const mix = require('laravel-mix');
const path = require('path');
require('laravel-mix-eslint');
require('laravel-mix-stylelint');

/*
 |--------------------------------------------------------------------------
 | Mix Asset Management
 |--------------------------------------------------------------------------
 |
 | Mix provides a clean, fluent API for defining some Webpack build steps
 | for your Laravel application. By default, we are compiling the Sass
 | file for the application as well as bundling up all the JS files.
 |
 */

const styleLintPlugin = require('stylelint-webpack-plugin');
mix.webpackConfig({
    plugins: [
        new styleLintPlugin({
            files: ['**/*.scss'],
            configFile: path.join(__dirname, '.stylelintrc.js'),
            syntax: 'scss'
        })
    ]
}).eslint();
mix.js('resources/js/app.js', 'public/js')
    .sass('resources/sass/app.scss', 'public/css')
    .browserSync({
        files: [
            'resources/views/**/*.blade.php',
            'public/**/*.*',
            'routes/**/*.php',
            '**/*.php'
        ],
        proxy: {
            target: 'http://127.0.0.1:8000/'
        }
    });

index.blade.php

php
<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>index</title>
</head>

<body>
    <div id="app">
        <example-component>
        </example-component>
    </div>
    <script src="{{ mix('js/app.js')}}"></script>
</body>

</html>

package.json

json
{
    "private": true,
    "scripts": {
        "dev": "npm run development",
        "development": "cross-env NODE_ENV=development node_modules/webpack/bin/webpack.js --progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js",
        "watch": "npm run development -- --watch",
        "watch-poll": "npm run watch -- --watch-poll",
        "hot": "cross-env NODE_ENV=development node_modules/webpack-dev-server/bin/webpack-dev-server.js --inline --hot --config=node_modules/laravel-mix/setup/webpack.config.js",
        "prod": "npm run production",
        "production": "cross-env NODE_ENV=production node_modules/webpack/bin/webpack.js --no-progress --hide-modules --config=node_modules/laravel-mix/setup/webpack.config.js"
    },
    "devDependencies": {
        "axios": "^0.19",
        "bootstrap": "^4.0.0",
        "browser-sync": "^2.26.7",
        "browser-sync-webpack-plugin": "^2.0.1",
        "cross-env": "^5.1",
        "eslint": "^6.8.0",
        "eslint-loader": "^3.0.3",
        "eslint-plugin-vue": "^6.0.1",
        "jquery": "^3.2",
        "laravel-mix": "^4.0.7",
        "laravel-mix-eslint": "^0.1.3",
        "laravel-mix-stylelint": "^0.2.0",
        "lodash": "^4.17.13",
        "popper.js": "^1.12",
        "resolve-url-loader": "^2.3.1",
        "sass": "^1.20.1",
        "sass-loader": "7.*",
        "stylelint": "^12.0.0",
        "stylelint-config-recommended-scss": "^4.1.0",
        "stylelint-scss": "^3.13.0",
        "stylelint-webpack-plugin": "^1.1.2",
        "vue": "^2.5.17",
        "vue-template-compiler": "^2.6.10"
    }
}