message: chore(vue): Update README for Vue 3
diff: This package is a wrapper around `@sentry/browser`, with added functionality related to Vue.js. All methods available in
  `@sentry/browser` can be imported from `@sentry/vue`.
  -It targets Vue version `2.x`. Support for `3.x` is tracked by [GitHub issue #2925](https://github.com/getsentry/sentry-javascript/issues/2925).
  +To use this SDK, call `Sentry.init(options)` as early in your application as possible.
  -To use this SDK, call `Sentry.init(options)` before you create a new Vue instance.
  +### Vue 3
  +
  +```javascript
  +const app = createApp({
  + // ...
  +});
  +
  +Sentry.init({
  + app,
  + dsn: '__PUBLIC_DSN__',
  +});
  +```
  +
  +### Vue 2
  ```javascript
  import Vue from 'vue'
  