Add integration test for pdeathsig behavior

Author: fahedouch

.github/workflows/main.yaml

@@ -52,6 +52,8 @@ jobs:
       run: docker run  --rm --privileged --sysctl net.ipv6.conf.all.disable_ipv6=0 rootlesskit:test-integration ./integration-ipv6.sh
     - name: "Integration test: systemd socket activation"
       run: docker run --rm --net=none --privileged rootlesskit:test-integration ./integration-systemd-socket.sh
+    - name: "Integration test: pdeathsig"
+      run: docker run --rm --privileged rootlesskit:test-integration ./integration-pdeathsig.sh
     - name: "Integration test: Network (network driver=slirp4netns)"
       run: |
         docker run --rm --privileged rootlesskit:test-integration ./integration-net.sh slirp4netns