ci: Trigger dependency audit on deny.toml change

Audit should run if `deny.toml` is modified, to check the updated policy.

Author: v0-e

.github/workflows/dependency-audit.yml

@@ -5,6 +5,7 @@ on:
     paths:
       - '**/Cargo.toml'
       - '**/Cargo.lock'
+      - 'deny.toml'
 
 env:
   CARGO_TERM_COLOR: always