Upgrade electron-builder, electron-builder-squirrel-windows to latest

package.json

@@ -107,8 +107,8 @@
     "cpx": "^1.3.2",
     "cross-env": "^4.0.0",
     "css-loader": "^2.1.0",
-    "electron-builder": "^20.38.5",
-    "electron-builder-squirrel-windows": "^20.38.5",
+    "electron-builder": "^20.44.4",
+    "electron-builder-squirrel-windows": "^21.0.6",
     "electron-devtools-installer": "^2.2.4",
     "eslint": "^5.8.0",
     "eslint-config-google": "^0.7.1",
@@ -159,7 +159,10 @@
       "src/**"
     ],
     "extraResources": [
-      { "from": "electron_app/img", "to": "img" },
+      {
+        "from": "electron_app/img",
+        "to": "img"
+      },
       "webapp/**/*",
       "origin_migrator/**/*"
     ],