Update .gitlab-ci.yml file

.gitlab-ci.yml

@@ -39,6 +39,7 @@ unit-test-job:   # This job runs in the test stage.
   stage: test    # It only starts when the job in the build stage completes successfully.
   script:
     - echo "Running unit tests..."
+    - apt-get -y update
     - apt-get -y install python3
     - source ansible/bin/activate
     - which ansible-playbook