add -q to pip install in .gitlab-ci.yml file

docs:userguide:

  image: sphinxdoc/sphinx:latest

  script:

    - pip install sphinx_rtd_theme sphinx_tabs

    - pip install -q sphinx_rtd_theme sphinx_tabs

    - sphinx-build -b html docs/source_docs/ build/docs

    - sphinx-build -b html docs/picvva/ build/picvva

  stage: build-docs