How to set up selenium/standalone-chrome with Zyte/Crawlera?

Dear people of Zyte, I am trying to use your service. 

I am using a Selenium Grid using this docker image:

- https://github.com/SeleniumHQ/docker-selenium

I have configured my docker-compose:

version: '3'
services:
  # Other services ...

  selenium_grid:
    image: selenium/standalone-chrome:4.0.0-beta-3-20210426
    volumes:
      - /dev/shm:/dev/shm
    environment:
      - SE_NODE_SESSION_TIMEOUT=30
      - SE_NODE_MAX_SESSIONS=5
      - SE_NODE_OVERRIDE_MAX_SESSIONS=true
    ports:
      - 4444:4444
      - 7900:7900

But I don't know how to add the proxy configuration. 

I have been reading and trying things, I was not able to configure it using the Watir (Ruby) browser creation: 

- https://github.com/watir/watir/issues/933

Also I was not lucky trying to add the configuration in the docker-compose it self:

- https://stackoverflow.com/questions/67654261/how-to-configure-proxy-in-selenium-standalone-chrome-docker-image-using-my-docke

Any suggestion from your side?

Thanks

f.