Add a validation for RuboCop's config/default.yml for supported styles other than EnforcedStyle
Add a validation for RuboCop's config/default.yml for supported styles other than EnforcedStyle

This is almost same validation to RuboCop::Config#validate_enforced_styles.
https://github.com/rubocop-hq/rubocop/blob/v0.68.0/lib/rubocop/config.rb#L545-L550

vergenzt/rubocop,deivid-rodriguez/rubocop,bbatsov/rubocop,jmks/rubocop,jfelchner/rubocop,tejasbubane/rubocop,tdeo/rubocop,tdeo/rubocop,panthomakos/rubocop,maxjacobson/rubocop,smakagon/rubocop,tejasbubane/rubocop,jfelchner/rubocop,meganemura/rubocop,panthomakos/rubocop,rrosenblum/rubocop,vergenzt/rubocop,mikegee/rubocop,rrosenblum/rubocop,smakagon/rubocop,deivid-rodriguez/rubocop,meganemura/rubocop,vergenzt/rubocop,meganemura/rubocop,bbatsov/rubocop,maxjacobson/rubocop,maxjacobson/rubocop,mikegee/rubocop,tdeo/rubocop,rrosenblum/rubocop,panthomakos/rubocop,tejasbubane/rubocop,jmks/rubocop,jmks/rubocop,deivid-rodriguez/rubocop,jfelchner/rubocop,mikegee/rubocop