docs: point get started button to the per-environment setup docs

Thanks untitaker!

docs/src/pages/index.tsx

@@ -18,7 +18,10 @@ function HomepageHeader() {
         </Heading>
         <p className="hero__subtitle">{siteConfig.tagline}</p>
         <div className={styles.buttons}>
-          <Link className="button button--secondary button--lg" to="/docs/">
+          <Link
+            className="button button--secondary button--lg"
+            to="/docs/category/environments"
+          >
             Get started
           </Link>
         </div>