Improve RuboCop rules (compatibility to Code Climate) (#3636)

https://github.com/codeclimate/codeclimate-rubocop/blob/08f8de84ebfb39caa96391e23816877278f6441c/Gemfile.lock#L38
Code Climate is using RuboCop v0.46.0.

Change several rules to maintain compatibility.

app/services/suspend_account_service.rb

@@ -23,7 +23,7 @@ class SuspendAccountService < BaseService
       @account.notifications,
       @account.favourites,
       @account.active_relationships,
-      @account.passive_relationships
+      @account.passive_relationships,
     ].each do |association|
       destroy_all(association)
     end