ci: add check-style job to the test stage

.gitlab-ci.yml

@@ -32,6 +32,19 @@ build-openapi-scheme:
     paths:
       - $OPENAPI_JSON
 
+check-style:
+  stage: test
+  image: python:3.11-slim
+  before_script:
+    # we do this, because YAML anchors are not supported when executing locally
+    - python3 -m pip install --upgrade pip
+    - python3 -m pip install poetry
+    - poetry install --no-root --only=dev
+  script:
+    - poetry run flake8 program steering
+    - poetry run isort program steering
+    - poetry run black program steering
+
 run_test_cases:
   stage: test
   image: python:3.11-slim