Firefox uses script instead of service_worker

Author: Chris Blum

manifest.json

@@ -27,7 +27,8 @@
     }
   ],
   "background": {
-    "service_worker": "background.js"
+    "service_worker": "background.js",
+    "scripts": ["background.js"]
   },
   "permissions": ["activeTab", "storage", "clipboardWrite", "idle", "alarms"],
   "web_accessible_resources": [