docs(auth): update heading level for passwordless authentication section

Author: Ahmed Hamouda

src/pages/[platform]/build-a-backend/auth/set-up-auth/index.mdx

@@ -63,7 +63,7 @@ By default, your auth resource is scaffolded using `email` as the default login
 
 <InlineFilter filters={['android', 'angular', 'javascript', 'nextjs', 'react', 'react-native', 'swift', 'vue']}>
 
-### Enable passwordless authentication
+## Enable passwordless authentication
 
 You can enable passwordless authentication methods to provide a more secure and user-friendly experience: