chore: set background persistent to false

Author: josStorer

src/manifest.v2.json

@@ -26,7 +26,8 @@
   "background": {
     "scripts": [
       "background.js"
-    ]
+    ],
+    "persistent": false
   },
   "browser_action": {
     "default_popup": "popup.html?popup=true"