fixed manifest warning

Author: minutogit

src/manifest.json

@@ -1,7 +1,7 @@
 {
   "manifest_version": 2,
   "name": "PrioMailbox",
-  "version": "1.0.1",
+  "version": "1.0.2",
   "default_locale": "en",
   "description": "PrioMailbox organizes your emails in Thunderbird with intelligent, trainable tags. Important messages are highlighted, while unimportant ones are hidden.",
   "icons": {
@@ -18,7 +18,6 @@
   "permissions": [
     "messagesModify",
     "messagesRead",
-    "messagesUpdate",
     "storage",
     "menus",
     "notifications",