Service Container not starting

Hi there, I’m struggling getting service containers to run. This is my testbed:

name: Build Project
on: [push]

    runs-on: ubuntu-latest
        image: mariadb:11.4.2-ubi9
          - 3306:3306
          MARIADB_DATABASE: "test"
          MARIADB_USER: "test"
          MARIADB_PASSWORD: "test"
          MARIADB_ROOT_PASSWORD: "test"
      - name: install netcat
        run: apt-get -y update ; apt -y install netcat-openbsd 
      - name: try to connect to db
        run: nc -w5 -z -v db 3306 || nc -w5 -z -v localhost 3306 || sleep 600

Which fails at the second step with:

nc: getaddrinfo for host "db" port 3306: Temporary failure in name resolution
nc: connect to localhost ( port 3306 (tcp) failed: Connection refused
nc: connect to localhost (::1) port 3306 (tcp) failed: Cannot assign requested address

The problem seems to be that the DB container isn’t even started: docker ps only shows gitea, gitea runner and the build container, but not the service container. Also, when I’m inspecting the build container, I cannot see any links set up in the network configuration. Am I missing something, or is this scenario not yet supported by gitea?

I’m running gitea 1.22.0 via docker-compose and latest stable gitea runner (also via docker-compose)