Renaming Overview to Get started

Author: Maddy-Cloudflare

src/content/docs/cloudflare-one/email-security/setup/index.mdx

@@ -1,8 +1,11 @@
 ---
-title: Setup
+title: Get started
 pcx_content_type: navigation
 sidebar:
+  label: Get started
   order: 11
+  group:
+    label: Setup
 ---
 
 import { Markdown } from "~/components";