treewide: Add passthru.updateScript to gnome pkgs

`updateScript` lets us update packages automatically.
For packages that are hosted on the gnome mirror it's very easy to add
that. Inspired by https://github.com/NixOS/nixpkgs/issues/36150

pkgs/development/tools/misc/gob2/default.nix

@@ -1,11 +1,11 @@
-{ stdenv, fetchurl, pkgconfig, glib, bison, flex }:
+{ stdenv, fetchurl, pkgconfig, glib, bison, flex, gnome3 }:
 
 stdenv.mkDerivation rec {
-  name = "gob2-${minVer}.20";
-  minVer = "2.0";
+  pname = "gob2";
+  version = "2.0.20";
 
   src = fetchurl {
-    url = "mirror://gnome/sources/gob2/${minVer}/${name}.tar.xz";
+    url = "mirror://gnome/sources/${pname}/${stdenv.lib.versions.majorMinor version}/${pname}-${version}.tar.xz";
     sha256 = "5fe5d7990fd65b0d4b617ba894408ebaa6df453f2781c15a1cfdf2956c0c5428";
   };
 
@@ -13,6 +13,13 @@ stdenv.mkDerivation rec {
   nativeBuildInputs = [ pkgconfig ];
   buildInputs = [ glib bison flex ];
 
+  passthru = {
+    updateScript = gnome3.updateScript {
+      packageName = pname;
+      versionPolicy = "none";
+    };
+  };
+
   meta = {
     description = "Preprocessor for making GObjects with inline C code";
     homepage = https://www.jirka.org/gob.html;