Update Cards -> CardGroup (#65)

Author: dannysheridan

fern/docs/pages/welcome.mdx

@@ -11,7 +11,7 @@ Welcome to the Plant Store API docs! This site demonstrates how to use Fern to g
 
 Here you'll find information about managing your plants, customers, and orders for your plant shop.
 
-<Cards>
+<CardGroup>
   <Card title="API Reference" icon="fa-solid fa-code" href="/api-reference" />
   <Card
     title="Discord Community"
@@ -28,7 +28,7 @@ Here you'll find information about managing your plants, customers, and orders f
     icon="fa-solid fa-shield-halved"
     href="https://security.buildwithfern.com"
   />
-</Cards>
+</CardGroup>
 
 ## Get support