fix : activate venv bfore installing

.gitlab/ci/ubuntu_python.gitlab-ci.yml

@@ -78,9 +78,9 @@ coverage:ubuntu_python:
   before_script: 
     - apt-get update
     - apt-get install -y python-is-python3 python3-pip
+    - source venv/bin/activate
     - python -m pip install numpy coverage requests
   script:
-    - source venv/bin/activate
     - cd ${CI_PROJECT_NAME}
     # Retrieve the installation path of the module, since it is installed with pip.
     - export MODULE_LOCATION=`python -c "import ${CI_PROJECT_NAME} as _; print(_.__path__[0])"`