test: bump node version

Author: kagawagao

.github/workflows/build.yml

@@ -10,6 +10,8 @@ jobs:
       - uses: actions/checkout@v1
       - name: Use Node.js
         uses: actions/setup-node@v1.1.0
+        with:
+          version: 14.x
       - name: npm install, test and build
         run: |
           npm ci