Fix update-from-upstream CI target

  before_script:

    - 'command -v ssh-agent >/dev/null || ( apt-get update -y && apt-get install openssh-client -y )'

    - eval $(ssh-agent -s)

    - echo "${SSH_E_ROBOT_PRIVATE_KEY}" | tr -d '\r' | ssh-add -

    - echo "${SSH_PRIVATE_KEY_ENV}" | tr -d '\r' | ssh-add -

    - mkdir -p ~/.ssh

    - chmod 700 ~/.ssh

    - echo "${SSH_KNOWN_HOSTS}" > ~/.ssh/known_hosts