gnomeExtensions.dash-to-dock: switch to fork to make it work with GNOME 40

pkgs/desktops/gnome/extensions/dash-to-dock/default.nix

@@ -2,22 +2,25 @@
 , fetchFromGitHub
 , glib
 , gettext
+, sassc
 }:
 
 stdenv.mkDerivation rec {
   pname = "gnome-shell-extension-dash-to-dock";
-  version = "69";
+  version = "unstable-2021-07-07";
 
+  # temporarily switched to https://github.com/micheleg/dash-to-dock/pull/1402 because upstream doesn't work with GNOME 40 yet.
   src = fetchFromGitHub {
-    owner = "micheleg";
+    owner = "ewlsh";
     repo = "dash-to-dock";
-    rev = "extensions.gnome.org-v" + version;
-    hash = "sha256-YuLtC7E8dK57JSuFdbDQe5Ml+KQfl9qSdrHdVhFaNiE=";
+    rev = "e4beec847181e4163b0a99ceaef4c4582cc8ae4c";
+    hash = "sha256-7UVnLXH7COnIbqxbt3CCscuu1YyPH6ax5DlKdaHCT/0=";
   };
 
   nativeBuildInputs = [
     glib
     gettext
+    sassc
   ];
 
   makeFlags = [