disable ci

.gitlab-ci.yml

-image: oarteam/batsim_ci:latest
-
-stages:
-  - big_stage
-
-figures:
-  stage: big_stage
-  script:
-    - nix-shell -A shell --command "ninja"
-  artifacts:
-    when: always
-    paths:
-      - ./pipe-usage-example.pdf