unsupported Compose file version: 2

docker-compose version 1.21.2, build a133471

version: '2'

services:
  caddy:
    build: .
    ports:
      - "80:80"
      - "443:443"
  portainer:
    image: portainer/portainer:latest
    ports:
      - "9000:9000"
    volumes:
      - "/var/run/docker.sock:/var/run/docker.sock"