Heroku Prisma Server upgrade

https://github.com/prisma/prisma-cloud-feedback/issues/202#issuecomment-414095090

I looked up prisma's latest docker hub tags at https://hub.docker.com/r/prismagraphql/prisma/tags/ and picked 1.14-heroku (not sure what the difference is in *-heroku tags, but it sounded reasonable. Could someone from Prisma explain the difference?)
I read Heroku's docs on docker deployment and followed this section: https://devcenter.heroku.com/articles/container-registry-and-runtime#pushing-an-existing-image.
Here's the exact steps I ran:

Pulled the docker image w/ the tag mentioned above: docker pull prismagraphql/prisma:1.34-heroku
Looked up the image id from the image I just pulled using: docker images
Using that image id, I tagged it to my Heroku repo: docker tag 6ff588b05d59 registry.heroku.com/${HEROKU_APP_NAME}/web

Need to login heroku container:login now


Pushed the image to my heroku repo: docker push registry.heroku.com/${HEROKU_APP_NAME}/web
Finally, release this image to Heroku: heroku container:release web --app=${HEROKU_APP_NAME}