web app manifest injection in PWA plugin missing quotes

[glalloue]

Version

4.5.6

Environment info

System:
    OS: Windows 10 10.0.16299
    CPU: (8) x64 Intel(R) Core(TM) i5-8350U CPU @ 1.70GHz
  Binaries:
    Node: 10.15.3 - C:\Program Files\nodejs\node.EXE
    Yarn: 1.21.1 - ~\AppData\Roaming\npm\yarn.CMD
    npm: 6.13.4 - C:\Program Files\nodejs\npm.CMD
  Browsers:
    Chrome: 85.0.4183.121
    Edge: Spartan (41.16299.1480.0)
  npmPackages:
    @fortawesome/vue-fontawesome: ^3.0.0-1 => 3.0.0-1
    @vue/babel-helper-vue-jsx-merge-props:  1.0.0
    @vue/babel-helper-vue-transform-on:  1.0.0-rc.2
    @vue/babel-plugin-jsx:  1.0.0-rc.3
    @vue/babel-plugin-transform-vue-jsx:  1.1.2
    @vue/babel-preset-app:  4.5.6
    @vue/babel-preset-jsx:  1.1.2
    @vue/babel-sugar-functional-vue:  1.1.2
    @vue/babel-sugar-inject-h:  1.1.2
    @vue/babel-sugar-v-model:  1.1.2
    @vue/babel-sugar-v-on:  1.1.2
    @vue/cli-overlay:  4.5.6
    @vue/cli-plugin-babel: ~4.5.6 => 4.5.6
    @vue/cli-plugin-eslint: ~4.5.6 => 4.5.6
    @vue/cli-plugin-pwa: ~4.5.0 => 4.5.6
    @vue/cli-plugin-router: ~4.5.6 => 4.5.6
    @vue/cli-plugin-typescript: ~4.5.6 => 4.5.6
    @vue/cli-plugin-vuex: ~4.5.6 => 4.5.6
    @vue/cli-service: ~4.5.6 => 4.5.6
    @vue/cli-shared-utils:  4.5.6
    @vue/compiler-core:  3.0.0-rc.10
    @vue/compiler-dom:  3.0.0-rc.10
    @vue/compiler-sfc: ^3.0.0-0 => 3.0.0-rc.10
    @vue/compiler-ssr:  3.0.0-rc.10
    @vue/component-compiler-utils:  3.2.0
    @vue/eslint-config-standard: ^5.1.2 => 5.1.2
    @vue/eslint-config-typescript: ^5.0.2 => 5.1.0
    @vue/preload-webpack-plugin:  1.1.2
    @vue/reactivity:  3.0.0-rc.10
    @vue/runtime-core:  3.0.0-rc.10
    @vue/runtime-dom:  3.0.0-rc.10
    @vue/shared:  3.0.0-rc.10
    @vue/web-component-wrapper:  1.2.0
    eslint-plugin-vue: ^7.0.0-0 => 7.0.0-beta.3
    typescript: ~3.9.3 => 3.9.7
    vue: ^3.0.0-0 => 3.0.0-rc.10
    vue-awesome-example:  2.0.0
    vue-class-component: ^8.0.0-0 => 8.0.0-alpha.6
    vue-eslint-parser:  7.1.0
    vue-hot-reload-api:  2.3.4
    vue-loader:  15.9.3 (16.0.0-beta.7)
    vue-router: ^4.0.0-0 => 4.0.0-beta.9
    vue-spinner: ^1.0.4 => 1.0.4
    vue-style-loader:  4.1.2
    vue-template-es2015-compiler:  1.9.1
    vuex: ^4.0.0-0 => 4.0.0-beta.4
    vuex-persistedstate: ^3.1.0 => 3.1.0
  npmGlobalPackages:
    @vue/cli: Not Found

Steps to reproduce

• create vue.Js (3.0) project
• add pwa plugin vue add pwa
• complete file vue.config.js with pwa configuration
• yarn build
• open 'index.html' in 'dist' repository and check 'manifest' link

What is expected?

line generated vue pwa vue-cli plugin should be:
<link rel=manifest href="/manifest.json">

What is actually happening?

line generated vue pwa vue-cli plugin is:
<link rel=manifest href=/manifest.json>

---

Quotes are html standard in this case and tools as PWA Builder (https://www.pwabuilder.com/) return error when we want to generate AppX windows package.
Related issue on PWA Builder team : pwa-builder/PWABuilder#1120