add package-manager version to workflow

Author: wuttinanhi

.github/workflows/astro-deploy-to-github-pages.yaml

@@ -22,6 +22,8 @@ jobs:
         uses: actions/checkout@v4
       - name: Install, build, and upload your site
         uses: withastro/action@v3
+        with:
+          package-manager: pnpm@latest
         # with:
           # path: . # The root location of your Astro project inside the repository. (optional)
           # node-version: 20 # The specific version of Node that should be used to build your site. Defaults to 20. (optional)