Fixed github workflow due to the latest directory structure change

Signed-off-by: Nicola Vigano <[email protected]>

.github/workflows/pythonpackage.yml

@@ -37,6 +37,7 @@ jobs:
         python -m pip install --upgrade pip setuptools build
         python -m pip install flake8 pytest
         python -m pip install -r requirements.txt
+        python -m pip install .
     - name: Lint with flake8
       run: |
         # stop the build if there are Python syntax errors or undefined names