Updated Mandrill Integration to Move to MailChimp

The email delivery service Mandrill officially closed as a separate service with a free tier. Instead, it is now available as part of the MailChimp email marketing service. API integrations in Thrive products were updated to support this change, so that you can use the Mandrill addon in MailChimp for email delivery. Of course, you can continue using MailChimp without Mandrill and you can replace Mandrill email delivery with one of the many other services we support.