add torch to examples requirements.

.github/workflows/test-ci.yml

@@ -162,7 +162,7 @@ jobs:
         run: |
           python -m pip install --upgrade pip
           python -m pip install -e .[test,dev]
-          python -m pip install finufft pooch brainweb-dl
+          python -m pip install finufft pooch brainweb-dl torch
 
       - name: Run examples
         shell: bash