Actually use .node-version

Author: mthierman

.github/workflows/build.yaml

@@ -24,6 +24,9 @@ jobs:
           run_install: true
 
       - uses: actions/setup-node@v6
+        with:
+          node-version-file: ".node-version"
+          cache: pnpm
 
       - id: pages
         uses: actions/configure-pages@v5