upgrade folsom

Hello 👋 I am the maintainer of folsom, long ago it moved to https://github.com/folsom-project/folsom when Boundary (the company I worked for) stopped existing. It looks like riak uses an old fork from the original project at https://github.com/boundary/folsom that I no longer have access to. I tagged 1.0 a while back and it might be good to upgrade https://github.com/folsom-project/folsom/releases/tag/1.0 and move over to the maintained repo.