GitHub Actions: deploy docs for each push on main

Author: dmerejkowsky

.github/workflows/doc.yml

@@ -32,3 +32,10 @@ jobs:
     - name: Build documentation
       run: |
         just build-doc
+
+    - name: Deploy to GitHub pages
+      uses: JamesIves/github-pages-deploy-action@v4.3.3
+      with:
+        token: ${{ secrets.GH_PAT }}
+        branch: gh-pages
+        folder: docs/_build/html/