Made install-once script work for both windows and mac

Co-authored-by: Justin Baik <bij3377@gmail.com>
Co-authored-by: Max Weisenberger <germanbluemax@gmail.com>
Co-authored-by: Mo Hmaidi <mhmaidi789@gmail.com>
Co-authored-by: Dieu Huynh <dieuhhuynh@gmail.com>

Author: 4 people

package.json

@@ -15,10 +15,10 @@
     },
     "linux": {
       "target": [
-      "deb"
+        "deb"
       ],
       "maintainer": "team spearmint"
-    } 
+    }
   },
   "main": "public/electron.js",
   "homepage": "./",
@@ -54,6 +54,7 @@
     "xterm-for-react": "^1.0.4"
   },
   "scripts": {
+    "install-once": "concurrently \"npm i\" \"npm run electron-rebuild\"",
     "test": "react-app-rewired test --env=jsdom",
     "test:e2e": "./node_modules/mocha/bin/mocha src/__tests__/spec.e2e.js",
     "test:integra": "mocha src/__tests__/spec.integra.js",