chore(3p): bump NixOS channels to 2022-01-12

Temporarily use a master commit as some interesting failures have been
fixed there (yubikey-manager and notmuch).

* //users/tazjin/nixos/camden: The acme module was moved around, so we
  need to adjust the disabled module path.

Change-Id: I21c6a1963ffe4205f3577f531ce10b778a82e2ff
Reviewed-on: https://cl.tvl.fyi/c/depot/+/4865
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>

users/tazjin/nixos/camden/default.nix

@@ -13,7 +13,7 @@ in lib.fix(self: {
   # Disable the current ACME module and use the old one from 19.09
   # instead, until the various regressions have been sorted out.
   # TODO(tazjin): Remove this once the new ACME module works.
-  disabledModules = [ "security/acme.nix" ];
+  disabledModules = [ "security/acme" ];
   imports =
     let oldChannel = fetchTarball {
       # NixOS 19.09 on 2020-10-04