Install cpu version of torch on ubuntu

.github/workflows/tests.yml

@@ -12,7 +12,9 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest, macOS-latest]
-        python: ['3.8', '3.7']
+        python: ['3.8']
+        torch: ['1.5.0']
+        torchvision: ['0.6.0']
     runs-on: ${{ matrix.os }}
 
     steps:
@@ -21,10 +23,18 @@ jobs:
       uses: actions/setup-python@v1
       with:
         python-version: ${{ matrix.python }}
-    - name: Install dependencies
+    - name: Install testing dependencies
       run: |
         python -m pip install --upgrade pip
         pip install pytest pytest-timeout
+    - name: Install torch on mac
+      if: startsWith(matrix.os, 'macOS')
+      run: pip install torch==${{ matrix.torch }} torchvision==${{ matrix.torchvision }}
+    - name: Install torch on ubuntu
+      if: startsWith(matrix.os, 'ubuntu')
+      run: pip install torch==${{ matrix.torch }}+cpu torchvision==${{ matrix.torchvision }}+cpu -f https://download.pytorch.org/whl/torch_stable.html
+    - name: Install requirements
+      run: |
         if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
         pip install scipy
         pip install git+https://github.com/mapillary/inplace_abn.git@v1.0.11