Add GH Pages workflow

Author: rzats

.github/workflows/documentation.yml

@@ -0,0 +1,29 @@
+name: documentation
+
+on: [push, pull_request, workflow_dispatch]
+
+permissions:
+  contents: write
+
+jobs:
+  docs:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
+      - name: Install dependencies
+        run: |
+          python3.8 -m venv .venv
+          .venv/bin/python -m pip install --upgrade pip
+          .venv/bin/pip install -e ".[dev]"
+      - uses: siacodelabs/setup-pandoc@v1
+      - name: Sphinx build
+        run: |
+          .venv/bin/sphinx-build -b html docs docs/_build
+      - name: Deploy to GitHub Pages
+        uses: peaceiris/actions-gh-pages@v3
+        with:
+          publish_branch: gh-pages
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: docs/_build/
+          force_orphan: true