Remove unused changelog
Remove unused changelog

While it would be nice to have a changelog, since this file has never been touched since the initial release, it creates confusion.
kathyonu/stripe-ruby-mock,hinthealth/stripe-ruby-mock,charitywater/stripe-ruby-mock,rebelidealist/stripe-ruby-mock,TrevorHinesley/stripe-ruby-mock,gravitystorm/stripe-ruby-mock,rebelidealist/stripe-ruby-mock