Use withastro/action@v2 with node 21.5.0

Author: emeraldjava

.github/workflows/build.yml

@@ -26,7 +26,7 @@ jobs:
       - name: Checkout your repository using git
         uses: actions/checkout@v4
       - name: Install, build, and upload your site output
-        uses: withastro/action@v2.0.1
+        uses: withastro/action@v2
         with:
           path: .
           node-version: 21.5.0