add dummy workflow to test GitHub Actions CI (#2697)

.github/workflows/test-workflow.yml

+name: scheduled-tests
+
+on:
+  schedule:
+    - cron: "*/30 * * * *"
+
+jobs:
+  download:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Set up python
+        uses: actions/setup-python@v2
+        with:
+          python-version: 3.6
+
+      - name: Upgrade pip
+        run: python -m pip install --upgrade pip
+
+      - name: Install PyTorch for CPU from the nightlies
+        run: |
+          pip install numpy
+          pip install --pre torch torchvision -f https://download.pytorch.org/whl/nightly/cpu/torch_nightly.html
+
+      - name: Install test requirements
+        run: pip install pytest pytest-subtests
+
+      - name: Simulate failing tests
+        run: exit 1
+
+      - name: Create issue for failed workflow
+        if: failure()
+        run: echo "Create an issue referencing this workflow run"