Add note about rollup@2 in Vite

Closes GH-2180.

Reviewed-by: Titus Wormer <tituswormer@gmail.com>

Author: Ryuujo Zhang

docs/docs/getting-started.server.mdx

@@ -346,6 +346,11 @@ If you use more modern JavaScript features than what your users support,
 [configure Vite’s
 `build.target`](https://vitejs.dev/guide/build.html#browser-compatibility).
 
+<Note type="info">
+  **Note**: Vite 3 requires the older `rollup@2`.
+  Make sure `rollup@3` is not installed.
+</Note>
+
 See also [¶ Rollup][rollup], which is used in Vite, and see [¶ Vue][vue], if
 you’re using that, for more info.