build_task:
  container:
    matrix:
      - image: ruby:latest
      - image: ruby:2.5
      - image: ruby:2.4
  bootstrap_script: gem install bundler
  bundler_cache:
    folder: /usr/local/bundle
    fingerprint_script: |
      cat Gemfile
      cat *.gemspec
    populate_script: bundler
  build_script: gem build *.gemspec
  gem_artifacts:
    path: ./jekyll-robotstxt-*.gem