Update rubocop config

The rubocop config introduced in #915 seems to have introduced a
duplicate line above the modulesync version.

Author: wyardley

.rubocop.yml

@@ -1,6 +1,4 @@
 ---
-inherit_from: .rubocop_todo.yml
-
 # Managed by modulesync - DO NOT EDIT
 # https://voxpupuli.org/docs/updating-files-managed-with-modulesync/