Update GitHub Actions workflow with correct permissions

.github/workflows/deploy.yml

@@ -0,0 +1,36 @@
+name: Deploy to GitHub Pages
+
+on:
+  push:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    permissions:
+      id-token: write
+      contents: read
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v2
+
+    - name: Set up Ruby
+      uses: actions/setup-ruby@v1
+      with:
+        ruby-version: 2.7
+
+    - name: Install dependencies
+      run: bundle install
+
+    - name: Build site
+      run: bundle exec jekyll build
+
+    - name: Deploy to GitHub Pages
+      uses: peaceiris/actions-gh-pages@v3
+      with:
+        github_token: ${{ secrets.GITHUB_TOKEN }}
+        publish_dir: ./_site
+