use tox -e docs instead of make docs inside xvfb-run

.gitlab-ci.yml

@@ -37,7 +37,7 @@ build_and_deploy_docs:
     before_script:
         - apt update
         - apt install -y graphviz libgl1-mesa-glx xvfb xdg-utils libcairo2-dev libjpeg-dev libgif-dev
-        - pip install awscli
+        - pip install tox awscli
     script:
         - echo "Bucket=${BUCKET_NAME}"
         - echo "AWS_DEFAULT_REGION=${AWS_DEFAULT_REGION}"