ci(gitlab-ci): use templates from a common repository

.gitlab-ci.yml

@@ -12,6 +12,7 @@
       - "templates/lint/check-dependencies-resolution.yml"  # will run pip-compile -n to check if dependencies are compatibles
       - "templates/lint/safety.yml"  # will run 'safety check --full-report' on the installed project
       - "templates/lint/flake8.yml"  # will do the equivalent of 'tox -e flake8'
+      - "templates/lint/black.yml"  # will do the equivalent of 'tox -e black'
       - "templates/lint/check-manifest.yml"  # will do the equivalent of 'tox -e check-manifest'
       - "templates/lint/yamllint.yml"  # will do the equivalent of 'tox -e yamllint'
       - "templates/tests/py3.yml"  # will do the equivalent of 'tox -e py3'