chore(3p): Bump NixOS channels to 2021-01-09

Your regularly scheduled channel update, but slightly more regular
than before.

Included fixes:

* 3p/emacs: Pick telega.el from stable channel, unstable is broken.
* glittershark/fprintd: Compile with gcc9, since build fails with the
  new default of gcc10
* glittershark/fprintd: Use a global overlay for the fprintd package
  until https://github.com/NixOS/nixpkgs/pull/108962 lands in
  nixos-unstable
* glittershark/home: Don't install rr, as it's not building with gcc10

Co-Author: Griffin Smith <grfn@gws.fyi>
Change-Id: Ia715fef64a405a220049fc540017356fa7370e0b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2341
Reviewed-by: tazjin <mail@tazj.in>
Reviewed-by: glittershark <grfn@gws.fyi>
Reviewed-by: lukegb <lukegb@tvl.fyi>
Tested-by: BuildkiteCI

users/glittershark/pkgs/fprintd/libfprint-tod.nix

@@ -22,7 +22,7 @@
 }:
 
 stdenv.mkDerivation rec {
-  pname = "libfprint";
+  pname = "libfprint-tod";
   version = "1.90.2";
   outputs = [ "out" "devdoc" ];