Update .gitlab-ci.yml (add - docker info in before script as in the docs)

.gitlab-ci.yml

@@ -8,6 +8,7 @@ before_script:
     - FRACTALIS_VERSION=$(grep version setup.py | grep -o "[0-9]\.[0-9]\.[0-9]")
     - DOCKER_IMAGE_TAG="fractalis:$FRACTALIS_VERSION"
     - SDIST=fractalis-$FRACTALIS_VERSION.tar.gz
+    - docker info
 
 stages:
     - build_sdist