Bugfix in import in workflow

Author: FBumann

.github/workflows/python-app.yaml

@@ -99,7 +99,7 @@ jobs:
           (sleep 30 && pip install --index-url https://test.pypi.org/simple/ --extra-index-url https://pypi.org/simple/ $PACKAGE_NAME) || \
           (sleep 60 && pip install --index-url https://test.pypi.org/simple/ --extra-index-url https://pypi.org/simple/ $PACKAGE_NAME)
           # Basic import test
-          python -c "import $PACKAGE_NAME; print('Installation successful!')"
+          python -c "import flixOpt; print('Installation successful!')"
 
   publish-pypi:
     name: Publish to PyPI