Add HubSpot example app to HubSpot docs (#332)

Author: mintlify[bot]

docs/integrations/hubspot.mdx

@@ -273,3 +273,16 @@ When you create a deal in HubSpot for a contact who came through your Dub links,
 When a deal moves to a **Closed Won** status in HubSpot, the integration automatically [tracks a sale event](/docs/quickstart/server#tracking-sale-events) in Dub using the deal amount as the sale value.
 
 If a deal is not being tracked as a sale in Dub, make sure you've set the correct Closed Won Deal Stage ID in your [HubSpot Integration Settings](#set-your-closed-won-deal-stage-id).
+
+## Example apps
+
+<CardGroup cols={2}>
+  <Card
+    title="Dub + HubSpot Demo App"
+    icon="github"
+    href="https://github.com/dubinc/examples/tree/main/conversions/hubspot"
+    color="#333333"
+  >
+    See the full example on GitHub.
+  </Card>
+</CardGroup>