bump node version (#56)

Author: typotter

.github/workflows/test-sdks.yml

@@ -87,10 +87,10 @@ jobs:
         uses: actions/checkout@v3
         with:
           repository: 'Eppo-exp/node-server-sdk'
-      - name: Use Node.js 16
+      - name: Use Node.js 18
         uses: actions/setup-node@v1
         with:
-          node-version: '16.x'
+          node-version: '18.x'
       - uses: actions/cache@v2
         with:
           path: './node_modules'