Add smoke tests script

Author: osalpekar

.github/workflows/build-conda-linux.yml

@@ -25,7 +25,7 @@ jobs:
             pre-script: ""
             post-script: ""
             conda-package-directory: packaging/torchvision
-            # TODO: Add smoke-test script once it's ready.
+            smoke-test-script: test/smoke_test.py
             package-name: torchvision
     name: ${{ matrix.repository }}
     uses: pytorch/test-infra/.github/workflows/build_conda_linux.yml@main