Install dynamic-lib dependency

Author: richardpringle

.github/workflows/tests.yaml

@@ -259,6 +259,9 @@ jobs:
       - name: Setup build dependencies
         uses: ./.github/actions/setup-build-deps
 
+      - name: Install libpcap
+        run: sudo apt-get update && sudo apt-get install -y libpcap-dev
+
       - name: Use shared OCaml setting up steps
         uses: ./.github/actions/setup-ocaml
         with: