add torch requirements to documentation github action

.github/workflows/ci-pipeline.yml

@@ -63,7 +63,7 @@ jobs:
  python-version: 3.9
  - name: Install dependencies
  run: |
- pip install torch torchvision --index-url https://download.pytorch.org/whl/cpu
+ pip install -r test/torch_requirements.txt
  pip install -r docs/requirements.txt
  pip install .
  - name: Build documentation