add workflow

.github/workflows/build_deploy.yml

@@ -0,0 +1,46 @@
+name: build and deploy the demo
+
+on:
+  push:
+    branches: [ master ]
+
+
+jobs:
+  build-deploy:
+    runs-on: ubuntu-20.04
+    steps:
+        - name: Checkout repo
+          uses: actions/checkout@v1
+          with:
+            submodules: true
+
+        - name: Setup Python
+          uses: actions/setup-python@v1
+          with:
+            python-version: '3.8'
+            architecture: 'x64'
+
+        - name: Cache dependencies
+          uses: actions/cache@v1
+          with:
+            path: ~/.cache/pip
+            key: ${{ runner.os }}-pip-${{ hashFiles('**/requirements.txt') }}
+            restore-keys: |
+              ${{ runner.os }}-pip-
+
+        - name: Install dependencies
+          run: |
+            python3 -m pip install --upgrade pip
+            python3 -m pip install -r ./requirements.txt
+            python3 -m pip install .
+      
+        - name: Sphinx Build
+          run: cd demo && make html
+
+        - name: Deploy
+          uses: peaceiris/actions-gh-pages@v3
+          with:
+            github_token: ${{ secrets.GITHUB_TOKEN }}
+            publish_dir: ./demo/_build/html/
+
+

requirements.txt

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+sphinx
+docutils