Update node and lock yarn

Author: dsh0416

.github/workflows/electron.yml

@@ -24,10 +24,10 @@ jobs:
       - uses: actions/checkout@v1
         with:
           fetch-depth: 1
-      - name: Use Node.js 10.x
+      - name: Use Node.js 12.x
         uses: actions/setup-node@v1
         with:
-          node-version: 10.x
+          node-version: 12.x
       - name: yarn install
         run: |
           yarn install