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/system/home/modules/development.nix

@@ -63,7 +63,6 @@ with lib;
     config.lib.depot.third_party.clang-tools
   ] ++ optionals (stdenv.isLinux) [
     valgrind
-    rr
   ];
 
   programs.git = {

users/glittershark/system/system/machines/yeren.nix

@@ -70,6 +70,11 @@
     intel-media-driver
   ];
 
+  # the fprintd module hardcodes pkgs.fprintd :'(
+  nixpkgs.overlays = [(_: _: {
+    fprintd = config.depot.users.glittershark.pkgs.fprintd;
+  })];
+
   services.fprintd = {
     enable = true;
     package = config.depot.users.glittershark.pkgs.fprintd;