Update pythonpackage.yml

.github/workflows/pythonpackage.yml

@@ -16,7 +16,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        pip install flake8 pytest
+        pip install .[dev]
     - name: Lint with flake8
       run: |
         # stop the build if there are Python syntax errors or undefined names