Mention Vue 3 incompatibility (#3704)

Author: kaovilai

src/wizard/javascript/vue.md

@@ -12,6 +12,8 @@ To begin collecting error and performance data from your Vue application, you'll
 - `@sentry/vue` (Sentry's Vue SDK)
 - `@sentry/tracing` (instruments performance data)
 
+Note: Vue 3 is not yet officially supported ([see issue](https://github.com/getsentry/sentry-javascript/issues/2925)).
+
 Below are instructions for using your favorite package manager, or alternatively loaded directly from our CDN.
 
 ### Using yarn or npm