chore: convert to pnpm and fix GitHub Actions workflow

.github/workflows/deploy.yml

@@ -11,19 +11,44 @@ permissions:
   id-token: write
 
 jobs:
-  deploy:
-    environment:
-      name: github-pages
-      url: ${{ steps.deployment.outputs.page_url }}
+  build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - name: Checkout your repository using git
+        uses: actions/checkout@v4
+
+      - name: Setup PNPM
+        uses: pnpm/action-setup@v2
+        with:
+          version: 8
+
+      - name: Setup Node
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: "pnpm"
+          cache-dependency-path: "./site/pnpm-lock.yaml"
+
+      - name: Install dependencies
+        working-directory: ./site
+        run: pnpm install --frozen-lockfile
+
+      - name: Build site
+        working-directory: ./site
+        run: pnpm build
 
       - name: Upload artifact
-        uses: actions/upload-pages-artifact@v1
+        uses: actions/upload-pages-artifact@v3
         with:
-          path: ./deploy
+          path: ./site/dist
 
+  deploy:
+    needs: build
+    runs-on: ubuntu-latest
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
       - name: Deploy to GitHub Pages
         id: deployment
         uses: actions/deploy-pages@v2