don't export derived, that leads to uPred being the wrong module

theories/base_logic/lib/fractional.v

 From stdpp Require Import gmap gmultiset.
-From iris.base_logic Require Export derived.
+From iris.base_logic Require Export base_logic.
 From iris.base_logic Require Import big_op.
 From iris.proofmode Require Import classes class_instances.
 Set Default Proof Using "Type".