Revert "Ignore derivative in Cargo deny (#3708)"

This reverts commit 59ef4df.

deny.toml

@@ -1,12 +1,6 @@
 # Copyright Kani Contributors
 # SPDX-License-Identifier: Apache-2.0 OR MIT
 
-[graph]
-# derivative is marked as unmaintained by RUSTSEC but still used in
-# Charon. We exclude it from the deny check until derivative is replaced
-# from Charon (https://github.com/AeneasVerif/charon/pull/459).
-exclude = ["derivative"]
-
 # This section is considered when running `cargo deny check advisories`
 # More documentation for the advisories section can be found here:
 # https://embarkstudios.github.io/cargo-deny/checks/advisories/cfg.html