Migrate off legacy CircleCI gpu executors (#134)

Summary:
Pull Request resolved: #134

Changing legacy GPU resource classes to `gpu.nvidia.small.multi`

Reviewed By: bigfootjon

Differential Revision: D33749817

fbshipit-source-id: c0ac419cb31c10a3198dabea8d5365459c081751

Author: Peter Romov

.circleci/config.yml

@@ -291,7 +291,7 @@ jobs:
     <<: *binary_common
     machine:
       image: ubuntu-1604-cuda-10.1:201909-23
-    resource_class: gpu.small
+    resource_class: gpu.nvidia.small.multi
     environment:
       image_name: "pytorch/manylinux-cuda101"
       PYTHON_VERSION: << parameters.python_version >>