Add security audit to CI.

.github/workflows/audit.yml

@@ -0,0 +1,27 @@
+name: "Audit Dependencies"
+
+on:
+  push:
+    paths:
+      # Run if workflow changes
+      - '.github/workflows/audit.yml'
+      # Run on changed dependencies
+      - '**/Cargo.toml'
+      - '**/Cargo.lock'
+      # Run if the configuration file changes
+      - '**/audit.toml'
+  schedule:
+    # run weekly
+    - cron: '0 0 * * 0'
+  workflow_dispatch:
+
+jobs:
+  audit:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      issues: write
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions-rust-lang/audit@v1
+        name: Audit Rust Dependencies