Error runner on Kubernetes managed cluster with no POSTGRESS_PASSWORD superuser

Since some days I'm experiencing problems running Gitlab CI runners on a managed Kubernetes. We used to be able to run the tests without setting a password but now it's required.

Looking at the logs of Kubernetes we can find why it's not running

Error: Database is uninitialized and superuser password is not specified. You must specify POSTGRES_PASSWORD for the superuser. Use "-e POSTGRES_PASSWORD=password" to set it in "docker run".

You may also use POSTGRES_HOST_AUTH_METHOD=trust to allow all connections without a password. This is not recommended. See PostgreSQL documentation about "trust": https://www.postgresql.org/docs/current/auth-trust.html

Setting a password for the superuser or adding POSTGRES_HOST_AUTH_METHOD=trust to the enviroment makes it run correctly.

Question is: did something changed in the GitLab CI managed kubernetes or did something change in Postgres that got this errror message?

Here the complete .gitlab-ci.yml that fails.

image: alpine:latest

variables:
  DOCKER_DRIVER: overlay2

cache:
  paths:
    - vendor/ruby
    - node_modules
  key: web-cache

before_script: &default
  - ruby -v
  - which ruby
  - gem install bundler
  - bundle install -j $(nproc) --path vendor

rspec:
  image: ruby:2.6.5
  before_script:
    - apt-get update -qq && apt-get install apt-transport-https ca-certificates libnss3 -y
    - curl -sL https://deb.nodesource.com/setup_12.x | bash -
    - curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | apt-key add -
    - echo "deb https://dl.yarnpkg.com/debian/ stable main" | tee /etc/apt/sources.list.d/yarn.list
    - apt-get update -qq && apt-get install nodejs yarn -y
    - ruby -v
    - which ruby
    - gem install bundler
    - bundle install -j $(nproc) --path vendor
    - yarn install
  script:
    - bundle exec rails db:test:prepare
    - bundle exec rspec
  artifacts:
    when: on_failure
    expire_in: 1 week
    paths:
      - tmp/screenshots/
      - log/
  services:
    - postgres:latest
    - redis:latest
    - selenium/standalone-chrome-debug:latest
  variables:
    POSTGRES_HOST: localhost
    POSTGRES_DB: test
    POSTGRES_USER: postgres
    POSTGRES_PASSWORD: ""
    REDIS_SERVER: redis://localhost:6379/0
    SELENIUM_URL: http://localhost:4444/wd/hub
    DOCKER_COMPOSE: 'true'

rubocop:
  image: ruby:2.6.5
  script:
    - bundle exec rubocop

brakeman:
  image: ruby:2.6.5
  script:
    - bundle exec brakeman