Add docs build and deploy workflow

Author: asmeurer

.github/workflows/docs.yml

@@ -0,0 +1,30 @@
+name: Docs
+on: [push, pull_request]
+jobs:
+  docs:
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+    environment:
+      name: docs-build-and-deploy
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-python@v2
+      - name: Install Dependencies
+        run: |
+          python -m pip install -r docs/requirements.txt
+
+      - name: Build Docs
+        run: |
+          cd docs
+          make html
+
+      # Note, the gh-pages deployment requires setting up a SSH deploy key.
+      # See
+      # https://github.com/JamesIves/github-pages-deploy-action/tree/dev#using-an-ssh-deploy-key-
+      - name: Deploy
+        uses: JamesIves/github-pages-deploy-action@v4
+        if: ${{ github.ref == 'refs/heads/main' }}
+        with:
+          folder: docs/_build/html
+          ssh-key: ${{ secrets.DEPLOY_KEY }}