docs: Fix package specifier

Author: Joepocalyptic

README.md

@@ -70,7 +70,7 @@ Example:
 </template>
 
 <script setup lang="ts">
-import type { Container } from 'tsparticles-engine'
+import type { Container } from '@tsparticles/engine'
 
 const options = {
   // See https://particles.js.org/docs/interfaces/tsParticles_Engine.Options_Interfaces_IOptions.IOptions.html