Update python-app.yml

to install torch on cpu

.github/workflows/python-app.yml

@@ -27,6 +27,8 @@ jobs:
       run: |
         python -m pip install --upgrade pip
         pip install flake8 pytest
+        # Install cpu torch first
+        pip install torch torchvision --index-url https://download.pytorch.org/whl/cpu
         if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
     - name: Lint with flake8
       run: |