Update electron requirement in /packages/generator/app/templates

Updates the requirements on [electron](https://github.com/electron/electron) to permit the latest version.
- [Release notes](https://github.com/electron/electron/releases)
- [Commits](electron/electron@v5.0.8...v6.0.0)

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

packages/generator/app/templates/package.json

@@ -53,7 +53,7 @@
     "chai-as-promised": "^7.1.1",
     "chai-dom": "^1.8.1",
     "chai-enzyme": "1.0.0-beta.1",
-    "electron": "^5.0.8",
+    "electron": "^6.0.0",
     "enzyme": "^3.10.0",
     "enzyme-adapter-react-16": "^1.14.0",
     "eslint": "^5.16.0",