Update buildtest.yml

Author: mskian

.github/workflows/buildtest.yml

@@ -13,7 +13,7 @@ jobs:
     - uses: actions/checkout@v3.0.2
     - uses: actions/setup-node@v3.4.1
       with:
-         node-version: '16.x'
+         node-version: '18.x'
     - name: use node
       run: |
        npm install