docs: add Apple App Store to showcase

Author: wyMinLwin

apps/svelte.dev/src/routes/showcase/+page.svelte

@@ -1,5 +1,10 @@
 <script>
 	const showcaseItems = [
+		{
+			title: 'Apple App Store',
+			image: '/showcase/apps.apple.png',
+			link: 'https://apps.apple.com/'
+		},
 		{
 			title: 'Apple Music',
 			image: '/showcase/music.apple.png',