[examples] Update svelte example with latest rollup (#5404)

Updated the template using `npx degit sveltejs/template my-svelte-project`

I also added a `yarn.lock` file so dependencies don't break for future deployments.

Related to https://github.com/Samuel-Martineau/generator-svelte/issues/7

examples/svelte/src/main.js

@@ -1,10 +1,10 @@
 import App from './App.svelte';
 
 const app = new App({
-  target: document.body,
-  props: {
-    name: 'world',
-  },
+	target: document.body,
+	props: {
+		name: 'world'
+	}
 });
 
-export default app;
+export default app;