[fix] #98 fix gitlab-ci tests task

Use make tests command

.gitlab-ci.yml

@@ -46,7 +46,6 @@ image: registry.duniter.org/docker/python3/duniterpy-builder:0.0.4
       - requirements_dev.txt
       - requirements.txt
       - setup.py
-      - tests/**/*.py
 
 .release_pip: &release_pip
   script:
@@ -68,9 +67,8 @@ test:
   <<: *changes
   stage: test
   script:
-    - pip install coveralls
     - pip install -r requirements.txt
-    - coverage run --source=duniterpy setup.py test
+    - make tests
 
 check:
   <<: *pyenv