Add rubocop-i18n to extensions page
Add rubocop-i18n to extensions page

I'm one of the maintainers on the rubocop-i18n project, and I'd like to add it to the "Known Custom Cops" list.
rrosenblum/rubocop,vergenzt/rubocop,maxjacobson/rubocop,palkan/rubocop,palkan/rubocop,bbatsov/rubocop,meganemura/rubocop,meganemura/rubocop,deivid-rodriguez/rubocop,tejasbubane/rubocop,smakagon/rubocop,tejasbubane/rubocop,mikegee/rubocop,sue445/rubocop,deivid-rodriguez/rubocop,tdeo/rubocop,meganemura/rubocop,petehamilton/rubocop,tdeo/rubocop,jmks/rubocop,tejasbubane/rubocop,maxjacobson/rubocop,jfelchner/rubocop,rrosenblum/rubocop,sue445/rubocop,deivid-rodriguez/rubocop,jfelchner/rubocop,mikegee/rubocop,bbatsov/rubocop,rrosenblum/rubocop,jfelchner/rubocop,panthomakos/rubocop,palkan/rubocop,bquorning/rubocop,tdeo/rubocop,mikegee/rubocop,vergenzt/rubocop,vergenzt/rubocop,jmks/rubocop,sue445/rubocop,maxjacobson/rubocop,panthomakos/rubocop,jmks/rubocop,bquorning/rubocop,panthomakos/rubocop,bquorning/rubocop,petehamilton/rubocop,smakagon/rubocop,petehamilton/rubocop