DEV: update rubocop to version 0.77

We like to stay as close as possible to latest with rubocop cause the cops
get better.

This update required some code changes, specifically the default is to avoid
explicit returns where implicit is done

Also this renames a few rules

script/import_scripts/mybb.rb

@@ -190,14 +190,14 @@ class ImportScripts::MyBB < ImportScripts::Base
     if quoted_post_id_from_imported
       begin
         post = Post.find(quoted_post_id_from_imported)
-        return "post:#{post.post_number}, topic:#{post.topic_id}"
+        "post:#{post.post_number}, topic:#{post.topic_id}"
       rescue
         puts "Could not find migrated post #{quoted_post_id_from_imported} quoted by original post #{post_id} as #{quoted_post_id}"
-        return ""
+        ""
       end
     else
       puts "Original post #{post_id} quotes nonexistent post #{quoted_post_id}"
-      return ""
+      ""
     end
   end