[test] Use PyTorch v1.5 for ci (#7)

.circleci/config.yml

@@ -42,6 +42,7 @@ install_dep: &install_dep
   - run:
       name: Install Dependencies
       command: |
+        pip install --progress-bar off torch==1.5.1+cu101 -f https://download.pytorch.org/whl/torch_stable.html
         pip install --progress-bar off -r requirements-test.txt
         python -c 'import torch; print("Torch version:", torch.__version__)'
         python -m torch.utils.collect_env

requirements-test.txt

@@ -4,6 +4,6 @@ isort == 4.3.21
 mypy == 0.770
 pytest == 5.4.1
 torchtext == 0.6.0
-torch == 1.4.0
-# NOTE(msb) not a dependency but needed by torch == 1.4.0
+torch == 1.5.1
+# NOTE(msb) not a dependency but needed by torch
 numpy == 1.17.4