pipeline: run pytest before pylint & mypy to distinguish python version specific incompatibilities from false positive linter errors

.github/workflows/python.yml

@@ -34,6 +34,7 @@ jobs:
            pipenv install --dev importlib-metadata;
            fi
     - run: pipenv graph
+    - run: pipenv run pytest --cov=ical2vdir --cov-report=term-missing --cov-fail-under=100
     - run: pipenv run pylint --load-plugins=pylint_import_requirements ical2vdir
     # https://github.com/PyCQA/pylint/issues/352
     # disable parse-error due to:
@@ -41,7 +42,6 @@ jobs:
     # > [Errno 2] No such file or directory: 'tests/resources/__init__.py' (parse-error)
     - run: pipenv run pylint --disable=parse-error tests/*
     - run: pipenv run mypy ical2vdir tests
-    - run: pipenv run pytest --cov=ical2vdir --cov-report=term-missing --cov-fail-under=100
     # >=1.9.0 to detect branch name
     # https://github.com/coveralls-clients/coveralls-python/pull/207
     # https://github.com/coverallsapp/github-action/issues/4#issuecomment-547036866