doc: note update of Ruby on Rails 6.1 pacakges to 6.1.6

devel/ruby-activesupport61
devel/ruby-activemodel61
devel/ruby-activejob61
www/ruby-actionview61
www/ruby-actionpack61
databases/ruby-activerecord61
devel/ruby-activestorage61
mail/ruby-actionmailer61
mail/ruby-actionmailbox61
www/ruby-actioncable61
devel/ruby-railties61
textproc/ruby-actiontext61
www/ruby-rails61

(taca)