Update .gitlab-ci.yml file

  tags:

    - git-run-ia2

  before_script:

    - apt-get update -y && apt install -y gnuplot

#    - apt-get update -y && apt install -y gnuplot

    - pip install --upgrade pip

    - pip install setuptools gnuplotlib pyvantagepro sphinx

#    - pip install gnuplotlib

    - pip install setuptools pyvantagepro sphinx

    - pip install -e .

    - pip install -r docs/requirements.txt

  script: