Deploy from GitLab to WPEngine (Tested)

.gitlab-ci.yml

stages:
  - deploy_dev
  - deploy_staging
  - deploy_live

before_script:
  - 'which ssh-agent || ( apk add --update openssh )'
  - apk add --update bash
  - apk add --update git
  - eval $(ssh-agent -s)
  - echo "$SSH_PRIVATE_KEY"
  - echo "$SSH_PRIVATE_KEY" | ssh-add -
  - mkdir -p ~/.ssh
  - '[[ -f /.dockerenv ]] && echo -e "Host *\n\tStrictHostKeyChecking no\n\n" > ~/.ssh/config'

Deploy Dev:
  stage: deploy_dev
  script:
    - git remote add dev $WPENGINE_DEV_GIT
    - "git checkout -b dev"
    - "git push dev HEAD:master --force"
  only:
    - develop

Deploy Staging:
  stage: deploy_staging
  script:
    - git remote add staging $WPENGINE_STAGING_GIT
    - "git checkout -b staging"
    - "git push staging HEAD:master --force"
  only:
    - master

Deploy Live:
  stage: deploy_live
  when: manual
  script:
    - git remote add live $WPENGINE_LIVE_GIT
    - "git checkout -b live"
    - "git push live HEAD:master --force"
  only:
    - tags