fix issue where electron doesn't open with electron:dev task

"react-scripts start" launches a dev server on IPv4.
With Node 17+ on Windows, "wait-on http://localhost:3000" tries to connect over IPv6 and fails.
By changing the command to "wait-on http://127.0.0.1:3000", wait-on will make an IPv4 request and succeed, allowing electron to open.

Here's a related thread about other people running into this issue: jeffbski/wait-on#109

README.md

@@ -183,7 +183,7 @@ app.on('activate', () => {
 ```json
   "scripts": {
     "postinstall": "electron-builder install-app-deps",
-    "electron:dev": "concurrently \"cross-env BROWSER=none yarn start\" \"wait-on http://localhost:3000 && tsc -p electron -w\" \"wait-on http://localhost:3000 && tsc -p electron && electron .\"",
+    "electron:dev": "concurrently \"cross-env BROWSER=none yarn start\" \"wait-on http://127.0.0.1:3000 && tsc -p electron -w\" \"wait-on http://127.0.0.1:3000 && tsc -p electron && electron .\"",
     "electron:build": "yarn build && tsc -p electron && electron-builder",
 ```
 

package.json

@@ -28,7 +28,7 @@
     "build": "react-scripts build",
     "test": "react-scripts test",
     "postinstall": "electron-builder install-app-deps",
-    "electron:dev": "concurrently \"cross-env BROWSER=none yarn start\" \"wait-on http://localhost:3000 && tsc -p electron -w\" \"wait-on http://localhost:3000 && tsc -p electron && electron .\"",
+    "electron:dev": "concurrently \"cross-env BROWSER=none yarn start\" \"wait-on http://127.0.0.1:3000 && tsc -p electron -w\" \"wait-on http://127.0.0.1:3000 && tsc -p electron && electron .\"",
     "electron:build": "yarn build && tsc -p electron && electron-builder",
     "eject": "react-scripts eject"
   },