update ci

.github/workflows/ci.yml

@@ -19,7 +19,8 @@ jobs:
           python-version: 3.8
           cache: 'pip'
       - run: echo "cache_id=$(date --utc '+%V')" >> $GITHUB_ENV 
-      - run: pip install torch # because torch_scatter contains import torch in the setup.py, we have to install torch first
+      - run: pip install torch==2.3.0 # because torch_scatter contains import torch in the setup.py, we have to install torch first
+      - run: pip install torch-scatter -f https://data.pyg.org/whl/torch-2.3.0+cpu.html # it seems a wheel is necessary to install torch-scatter
       - name: regular install
         run: pip install .
       - name: attempt import