Setup concurrently script with wait-on

- Using concurrently to launch electron once react is running
- "start-react" script launches react with BROWSER=none to prevent default opening of a browser tab at launch
- "start-electron" script launches electron once wait-on received http 200 status code from http://127.0.0.1:3000
- Had to use 127.0.0.1 instead of "localhost" in the wait-on url, as wait-on can hang trying to resolve localhost. see wait-on github issues for further details (jeffbski/wait-on#109)
- Updated start script in package.json
- running npm start now launches react with BROWSER=none using cross-env, then launches electron-start to launch electron after the wait-on is successful

package.json

@@ -17,11 +17,12 @@
     "web-vitals": "^2.1.4"
   },
   "scripts": {
-    "start": "react-scripts start",
+    "start": "concurrently \"npm run start-react\" \"npm run start-electron\"",
+    "start-react": "cross-env BROWSER=none react-scripts start",
+    "start-electron": "wait-on http-get://127.0.0.1:3000 && electron .",
     "build": "react-scripts build",
     "test": "react-scripts test",
-    "eject": "react-scripts eject",
-    "start-electron": "electron ."
+    "eject": "react-scripts eject"
   },
   "eslintConfig": {
     "extends": [