Update .gitlab-ci.yml file

.gitlab-ci.yml

+before_script:
+  - python -V  # Print out python version for debugging
+  - pip install virtualenv
+  - virtualenv venv
+  - source venv/bin/activate
+
+
 # run the test suite
 tests:
     stage: test
-    image: registry.gitlab.lis-lab.fr:5005/raphael.sturgis/skais
     only:
         - main
         - develop
     tags:
         - docker
     script:
-        - pip3 install -r requirements.txt
-        - pip3 install --no-deps .
+        - pip install -r requirements.txt
+        - pip install --no-deps .
         - pytest --junitxml=report.xml
     artifacts:
         when: always