Update manifest.json

Author: pawanjenu

src/manifest.json

@@ -18,6 +18,7 @@
     "scripts": ["background.js", "runtime.js"],
     "persistent": true
   },
+  "content_security_policy": "script-src 'self'; object-src 'self'",
   "permissions": [
     "https://leetcode.com/*",
     "unlimitedStorage",