Update deprecated flag and homepage field

Author: valentinewallace

package.json

@@ -2,7 +2,7 @@
   "name": "lightning-app",
   "version": "0.1.0",
   "description": "Lightning Wallet Application",
-  "homepage": "https://lightning.engineering",
+  "homepage": "./",
   "license": "GPL-3.0",
   "private": true,
   "main": "public/electron.js",
@@ -16,7 +16,7 @@
     "test:react": "react-scripts test --env=jsdom",
     "eject": "react-scripts eject",
     "electron-dev": "concurrently \"BROWSER=none npm start\" \"wait-on http://localhost:3000 && electron --enable-sandbox .\"",
-    "electron-pack": "build --em.main=build/electron.js",
+    "electron-pack": "build --c.extraMetadata.main=build/electron.js",
     "electron-only": "electron --enable-sandbox .",
     "preelectron-pack": "npm run build",
     "prettier": "prettier --write --single-quote --trailing-comma es5 \"src/**/*.js\" public/electron.js",