GHA: Use step-security/harden-runner

Author: dalcinl

.github/workflows/update.yml

@@ -25,6 +25,10 @@ jobs:
 
     steps:
 
+    - uses: step-security/harden-runner@v2
+      with:
+        egress-policy: audit
+
     - name: Checkout
       uses: actions/checkout@v4