Luckily with Tasker you can bring it back! Check it out!
Just import the project from here and follow the instructions at the same link and you’ll have the Spotify widget back in no time!
As a bonus you can click the widget's title to change the app to control, so you can, for example, control both Spotify and Google Play Music with the same widget!
Don't forget to get AutoNotification and enable its Notification Access service (in Tasker > Menu > More > Android Settings > Notification Access > Enable AutoNotification) to get the album art to work.