Update python-package.yml

.github/workflows/python-package.yml

@@ -27,7 +27,7 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        python -m pip install flake8 pytest django
+        python -m pip install flake8 pytest django Pillow
     - name: Lint with flake8
       run: |
         # stop the build if there are Python syntax errors or undefined names