zotero: fix reliance on coreutils being in PATH

zotero currently fails in pure environments with:

.zotero-wrapped: line 12: readlink: command not found
.zotero-wrapped: line 12: dirname: command not found
.zotero-wrapped: line 13: /zotero-bin: No such file or directory

Because the script assumes that readlink and dirname are
available. Fix by adding coreutils to PATH using the wrapper.

pkgs/applications/office/zotero/default.nix

@@ -1,6 +1,7 @@
 { stdenv, fetchurl, wrapGAppsHook, makeDesktopItem
 , atk
 , cairo
+, coreutils
 , curl
 , cups
 , dbus-glib
@@ -131,6 +132,12 @@ stdenv.mkDerivation rec {
          "$out/usr/lib/zotero-bin-${version}/{}" \;
   '';
 
+  preFixup = ''
+    gappsWrapperArgs+=(
+      --prefix PATH : ${stdenv.lib.makeBinPath [ coreutils ]}
+    )
+  '';
+
   meta = with stdenv.lib; {
     homepage = "https://www.zotero.org";
     description = "Collect, organize, cite, and share your research sources";