chore(v2): update examples to use alpha73 (#4631)

* regenerate examples on alpha73

* fix init template typo + add missing files

src/components/HomepageFeatures.js

@@ -0,0 +1,70 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+import React from 'react';
+import clsx from 'clsx';
+import styles from './HomepageFeatures.module.css';
+
+const FeatureList = [
+  {
+    title: 'Easy to Use',
+    Svg: require('../../static/img/undraw_docusaurus_mountain.svg').default,
+    description: (
+      <>
+        Docusaurus was designed from the ground up to be easily installed and
+        used to get your website up and running quickly.
+      </>
+    ),
+  },
+  {
+    title: 'Focus on What Matters',
+    Svg: require('../../static/img/undraw_docusaurus_tree.svg').default,
+    description: (
+      <>
+        Docusaurus lets you focus on your docs, and we&apos;ll do the chores. Go
+        ahead and move your docs into the <code>docs</code> directory.
+      </>
+    ),
+  },
+  {
+    title: 'Powered by React',
+    Svg: require('../../static/img/undraw_docusaurus_react.svg').default,
+    description: (
+      <>
+        Extend or customize your website layout by reusing React. Docusaurus can
+        be extended while reusing the same header and footer.
+      </>
+    ),
+  },
+];
+
+function Feature({Svg, title, description}) {
+  return (
+    <div className={clsx('col col--4')}>
+      <div className="text--center">
+        <Svg className={styles.featureSvg} alt={title} />
+      </div>
+      <div className="text--center padding-horiz--md">
+        <h3>{title}</h3>
+        <p>{description}</p>
+      </div>
+    </div>
+  );
+}
+
+export default function HomepageFeatures() {
+  return (
+    <section className={styles.features}>
+      <div className="container">
+        <div className="row">
+          {FeatureList.map((props, idx) => (
+            <Feature key={idx} {...props} />
+          ))}
+        </div>
+      </div>
+    </section>
+  );
+}