chore(3p): Bump nixpkgs channels

Bumps both nixos-unstable and nixos-20.03 to today's versions, as per
status.nixos.org

Contains minor fixes to things that broke because of the update:

* tazjin/frog: hardware.u2f is a deprecated setting
* glittershark/system: modSha256 in Go modules is now vendorSha256
* glittershark/owothia: removed version constraint on relude

Change-Id: Ib3e9612b1b06ed547b90e4f8b0ffe5ed7fe0a5c4
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1642
Tested-by: BuildkiteCI
Reviewed-by: glittershark <grfn@gws.fyi>

users/glittershark/owothia/owothia.cabal

@@ -5,7 +5,7 @@ version:             0.0.1.0
 executable owothia
   main-is:             Main.hs
   build-depends:       base
-                     , relude ^>= 0.6.0.0
+                     , relude
                      , irc-client
                      , lens
                      , chatter