This is a Heroku Buildpack for Caddy Server.
Include a Caddyfile in your repo.
Include static files in your repo.
Set your buildpack to
heroku config:add BUILDPACK_URL=https://github.com/nlozovan/caddy-buildpack-heroku.git
Based on this previously created buildpack: https://elements.heroku.com/buildpacks/fishman/buildpack-caddy . Credits should go to that owner.
Copy the snippet above into CLI.