If you do not want your subscription to auto-renew, simply log into your account and go to "Digital subscriptions". In the tab called "Subscriptions", click on the auto-renewal toggle to turn off this feature.
Once turned off, your subscription will no longer auto-renew.
*Please note: if you have set your Digital Subscription to auto-renew, you must cancel your Digital Subscription before it renews to avoid paying for the next Subscription Period.