Fastly now supports PFS

Fastly rolled out PFS support yesterday via ECDHE, so this updates the table. Let me know if you need more info for confirmation than [this SSLCheck report](https://sslcheck.casecurity.org/en_US/sslcheck?host=api.foursquare.com#199.27.73.184-srv), or if I've made an incorrect edit. cc @pyoungmeister