Update yaml codeblocks

doc/ci/caching/index.md

doc/ci/cloud_deployment/index.md

doc/ci/docker/using_kaniko.md

doc/ci/examples/end_to_end_testing_webdriverio/index.md

doc/ci/examples/laravel_with_gitlab_and_envoy/index.md

doc/ci/examples/php.md

...ci/examples/test-and-deploy-ruby-application-to-heroku.md

doc/ci/migration/circleci.md

doc/ci/migration/jenkins.md

doc/ci/pipelines/pipeline_architectures.md

doc/ci/review_apps/index.md

doc/ci/ssh_keys/README.md

doc/ci/variables/README.md

doc/ci/yaml/README.md