Add vendo button (#1806)

Author: myronkaifung

pages/docs/tracking-methods/integrations.mdx

@@ -34,4 +34,5 @@ you're looking for [reach out to us](https://mixpanel.com/get-support).
   <Cards.Card icon title="Snowplow" href="/docs/tracking-methods/integrations/snowplow" />
   <Cards.Card icon title="Stripe" href="/docs/tracking-methods/integrations/stripe" />
   <Cards.Card icon title="Tealium" href="/docs/tracking-methods/integrations/tealium" />
+  <Cards.Card icon title="Vendo" href="/docs/tracking-methods/integrations/vendo" />
 </Cards>