Update php version with Dockerfile

Thanks for the reply.

I’m not sure how to do that, because I can only apply 1 Dockerfile to the worker right?
My docker-compose.yml:

version: '3.4'

services:
  worker:
    build: .
    environment: 
      RUNNER_WORKDIR: /tmp/runner/work
      RUNNER_NAME_PREFIX: sam
      ORG_NAME: Emotion-nl
      RUNNER_SCOPE: org
      LABELS: node12,sam
      ACCESS_TOKEN: ghp_***************************************
      DISABLE_AUTO_UPDATE: "true"
      TZ: Europe/Amsterdam
    restart: always
    volumes:
      - '/var/run/docker.sock:/var/run/docker.sock'