update CI for pip 20.3 (open-mmlab#307)

* update CI for pip 20.3

* fixed 1.6 torchvision

* delete python 3.8

* fixed mmcv

* add cuda home

* change to 1.2.2

* add pip upgrade

* install cuda for all

* add missing mmcv

* switch to deprecate

Author: xvjiarui

.github/workflows/build.yml

@@ -36,7 +36,7 @@ jobs:
         torch: [1.3.0+cpu, 1.5.0+cpu]
         include:
           - torch: 1.3.0+cpu
-            torchvision: 0.4.2+cpu
+            torchvision: 0.4.1+cpu
           - torch: 1.5.0+cpu
             torchvision: 0.6.0+cpu
           - torch: 1.5.0+cpu
@@ -71,13 +71,13 @@ jobs:
           export PATH=${CUDA_HOME}/bin:${PATH}
           sudo apt-get install -y ninja-build
       - name: Install Pillow
-        if: ${{matrix.torchvision == '0.4.2+cpu'}}
+        if: ${{matrix.torchvision == '0.4.1+cpu'}}
         run: pip install Pillow==6.2.2
       - name: Install PyTorch
         run: pip install torch==${{matrix.torch}} torchvision==${{matrix.torchvision}} -f https://download.pytorch.org/whl/torch_stable.html
       - name: Install mmseg dependencies
         run: |
-          pip install mmcv-full==latest+torch${{matrix.torch}} -f https://download.openmmlab.com/mmcv/dist/index.html
+          pip install mmcv-full==latest+torch${{matrix.torch}} -f https://download.openmmlab.com/mmcv/dist/index.html --use-deprecated=legacy-resolver
           pip install -r requirements.txt
       - name: Build and install
         run: rm -rf .eggs && pip install -e .