Prevent "random-uuid already refers to" warning

In Clojure 1.11 the function random-uuid was introduced in clojure.core
causing:

> WARNING: random-uuid already refers to: #'clojure.core/random-uuid in namespace: monger.util, being replaced by: #'monger.util/random-uuid

src/clojure/monger/util.clj

@@ -32,6 +32,7 @@
 ;; ----------------------------------------------------------------------------------
 
 (ns ^{:doc "Provides various utility functions, primarily for working with document ids."} monger.util
+  (:refer-clojure :exclude [random-uuid])
   (:import java.security.SecureRandom
            java.math.BigInteger
            org.bson.types.ObjectId