split one test into three

(I am trying to debug the third one on the Mac, and this makes it easier.)

.gitlab-ci.yml

@@ -77,6 +77,7 @@ style:
     - *prepare_style
     - black --version
     - ruff --version
+    - pycodestyle --version
     - ruff .
     - black --check --diff .
     - pydocstyle mpsd-software-environment.py