tox: run only code-check

Author: myakove

.github/workflows/python-package.yml

@@ -28,7 +28,6 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         python -m pip install tox
-        if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
     - name: tox
       run: |
-       tox
+       tox -e code-check