Update 'Buy Now' links with the new Plan IDs.
With the addition of EE Starter and EE Premium plans new Rate Plans were created on Zuora. The Buy Now
links on the products page were pointing the old plan (GitLab EE), that's why I'm seeing that some customers have been purchasing the old plan.
I'm going to invalidate these plan IDs on the subscription portal as well, customers will be redirected to the plans listing page if they're using an invalid plan id in the URL.