use upload pages artifact instead of writing to gh-pages branch (#126)

.github/workflows/gh-pages.yml

@@ -7,38 +7,39 @@ on:
     paths:
       - 'README.md'
       - 'docs/book/**'
-  pull_request:
-     paths:
-      - 'README.md'
-      - 'docs/book/**'
+
+permissions:
+  contents: read
+  pages: write      # to deploy to Pages
+  id-token: write   # to verify the deployment originates from an appropriate source
 
 jobs:
-  deploy:
+  generate-docs:
     runs-on: ubuntu-latest
-    # Grant GITHUB_TOKEN the permissions required to make a Pages deployment
-
-    permissions:
-      pages: write      # to deploy to Pages
-      id-token: write   # to verify the deployment originates from an appropriate source
-
-    concurrency:
-      group: ${{ github.workflow }}-${{ github.ref }}
-
+    timeout-minutes: 2
     steps:
       - uses: actions/checkout@v4
-
       - name: Setup mdBook
         uses: peaceiris/actions-mdbook@v1
         with:
           mdbook-version: '0.4.35'
-
-      - run: cd docs/book && mdbook build
-
-      - name: Deploy
-        uses: peaceiris/actions-gh-pages@v3
-        if: ${{ github.ref == 'refs/heads/main' }}
+      - name: Setup Pages
+        uses: actions/configure-pages@v4
+      - name: Build with mdBook
+        run: cd docs/book && mdbook build
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
         with:
-          github_token: ${{ secrets.GITHUB_TOKEN }}
-          publish_dir: ./docs/book
-          user_name: 'github-actions[bot]'
-          user_email: 'github-actions[bot]@users.noreply.github.com'
+          path: 'docs/book/book'
+
+  deploy-page:
+    needs: generate-docs
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    timeout-minutes: 2
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4