add in workflow to publish docs

.github/workflows/build-docs.yml

@@ -0,0 +1,29 @@
+name: Sphinx build
+
+on:  # yamllint disable-line rule:truthy
+  workflow_call:
+
+jobs:
+  sphinx-build:
+    runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: ./doc
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Build HTML
+        run: make
+
+      - name: Upload artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: html-docs
+          path: ./html/
+
+      - name: Deploy
+        if: ${{ github.ref == 'refs/heads/master' }}
+        uses: peaceiris/actions-gh-pages@v3
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: ./html