Update README.md

Updated description permission change.

README.md

@@ -15,6 +15,6 @@ A simple per-tab automatic page refresher/reloader for Google Chrome.
   - storage - used to store default settings and save user preferences
   - contextMenus - used to enable the optional context (right click) menu for this extension
   - tabs - used to get the title from each tab (to be displayed in the options page)
-  - <all_urls> - used to execute the code to block reloads
+  - activeTab - used to execute the code to block reloads
 
 Warning: Some sites may restrict your access to them if you make too many requests (or reloads) within a short period of time.