Tests/docker (#1573)

* devel image

* try parallel

* new image

.github/workflows/ci-testing.yml

@@ -81,7 +81,7 @@ jobs:
       run: |
         # python -m pip install --upgrade --user pip
         pip install -r requirements.txt -U -f https://download.pytorch.org/whl/torch_stable.html -q
-        HOROVOD_BUILD_ARCH_FLAGS="-mfma" pip install -r ./tests/requirements.txt -q
+        HOROVOD_BUILD_ARCH_FLAGS="-mfma" pip install -r ./tests/requirements-devel.txt -q
         # pip install tox coverage
         python --version
         pip --version