Change developer CTA (#12857) (#12892)

* change `index.js`

(cherry picked from commit 9e7fad1fd2)

Co-authored-by: R. M. Shea <8948187+rmshea@users.noreply.github.com>

docs/src/pages/index.js

@@ -8,8 +8,8 @@ import styles from "./styles.module.css";
 
 const features = [
   {
-    title: <>⛏ Build an Application</>,
-    imageUrl: "apps",
+    title: <>⛏ Build Your First App</>,
+    imageUrl: "https://github.com/solana-labs/example-helloworld",
     description: <>Get started building your decentralized app or marketplace.</>,
   },
   {