This update introduced many breaking changes.
Listed here the most important ones:
* quasar.conf.js file has been renamed
quasar.config.js.
* Quasar v4 replaced the old /src/index.template.html
with a new /index.html at the root of the project.
The special comment <!-- quasar:entry-point -->
is used to inject scripts/styles automatically.
* Use setupMiddlewares instead of onBeforeSetupMiddleware.
* proxy is now an array of proxy config objects.
* Dropped support for Vuex. We can still use Vuex as any
Vue plugin, but we have to manage everything (installing the
store, no store parameter in boot files, etc.).
We'll migrate to Pinia asap.
* Updated postcssrc according to docs
Change-Id: I585a3e2d17f666d9ca2773fa446d644f0fc201a2