Update python-app.yml

Throwing everything at the wall to see what sticks

.github/workflows/python-app.yml

@@ -28,7 +28,7 @@ jobs:
         python -c "import sys; print('\n'.join(sys.path))"
     - name: Install dependencies
       run: |
-        python -m pip install --upgrade pip requirements.txt
+        python -m pip install --upgrade pip -r requirements.txt
         pip install -r requirements.txt
         pip install flake8 pytest
     - name: Check package location