Plan for Vue CLI v5

Here are the rough ideas:

Major Dependency Upgrades

Webpack 5 (also allows to opt-out to webpack 4), https://github.com/vuejs/vue-cli/pull/6060
HTML Webpack Plugin 4
Cypress 6, would be a peer dependency
Workbox 6
Jest 26
Mocha 8
ESLint 7
Other necessary major dependency version bumps, including various webpack loaders and plugins

Performance
- Now that we use webpack 5 by default, we can utilize its persistent cache to have a better compilation performance.
Predicatibility
- ~~A --transpile-all CLI flag to include node_modules for transpiration, as a fail-safe for the transpileDependencies option.~~ The transpileDependencies option can be set to true to transpile all dependencies in node_modules. It should be the recommended way to build your app, especially when you are using webpack 5, as the compilation overhead should be tolerable with the persistent cache.
Modern mode
- Enabled by default, with additional modern-only and no-modern CLI options
- A separate polyfills chunk by default
- Better browserslist integration. For example, safari-no-module-fix can be dropped when browserslist config does not target those buggy browsers.
Configuration
- Async config loading

vue serve/build will be an alias of npm run serve/build. If an entry is designated and no package.json found, it’ll prompt to use vite (Vue 3) or parcel (Vue 2) for instant prototyping instead.