ci: Update workflows

Author: OUDON

.github/workflows/python-app.yml

@@ -27,6 +27,7 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install flake8 pytest
+        pip install .
         if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
     - name: Lint with flake8
       run: |