The image is for running markdownlint-cli2, markdownlint-cli2 is installed
in /app/ in case you need to customize the install before usage.
The source could be find Documentation and more information
about rules and configuration could be found here: Rules
markdownlint-cli2:
  stage: linting
  image: registry.gitlab.com/pipeline-components/markdownlint-cli2:latest
  script:
    - markdownlint-cli2 .