Add github actions to update sphinx docs

.github/workflows/sphinx.yml

@@ -0,0 +1,19 @@
+name: "Sphinx: Render docs"
+
+on: push
+
+jobs:
+  pages:
+    runs-on: ubuntu-20.04
+    permissions:
+      contents: write
+    steps:
+    - id: deployment
+      uses: sphinx-notes/pages@v3
+      with:
+        publish: false
+        documentation_path: ./docs/source
+    - uses: peaceiris/actions-gh-pages@v4
+      with:
+        github_token: ${{ secrets.GITHUB_TOKEN }}
+        publish_dir: ${{ steps.deployment.outputs.artifact }}