Fastly supports NixOS

We are happy to announce that we have moved our binary cache to Fastly. Fastly is a big supporter of open source projects and now NixOS is one of them! Fastly provides us with CDN capability, which previously was running on AWS CloudFront. Big thanks go to Fastly, in particular Tom Denniston and Elaine Greenberg, our friends at Infor and and Graham Christensen for making this possible.