Change test workflow to run tests directly

.github/workflows/pythonapp.yml

@@ -9,14 +9,6 @@ jobs:
       uses: actions/setup-python@v1
       with:
         python-version: 3.x
-    - name: Install dependencies
-      run: |
-        python -m pip install --upgrade pip
-        pip install -r requirements.txt -r requirements-dev.txt
-    - name: Lint with flake8
-      run: |
-        # stop the build if there are Python syntax errors or undefined names
-        flake8 --count pgzero pgzrun.py test
     - name: Install xvfb
       run: |
           sudo apt-get install xvfb