Bump nixpkgs
Bump nixpkgs

This may help with darwin support for ghcjs

ajnsit/reflex-platform,ryantrinkle/try-reflex,reflex-frp/reflex-platform,reflex-frp/reflex-platform,ocharles/try-reflex,reflex-frp/reflex-platform,meiersi/try-blaze-react,jhegedus42/try-reflex,paldepind/try-reflex,unisonweb/unison-dependencies