[VOL-3054] Added flag -igmp to BBSim helm chart

Change-Id: I76cc726f98d2f46de4ea5b315e020fd8dafd8050
diff --git a/bbsim/templates/deployment.yaml b/bbsim/templates/deployment.yaml
index 7936d0f..59c513c 100644
--- a/bbsim/templates/deployment.yaml
+++ b/bbsim/templates/deployment.yaml
@@ -63,6 +63,9 @@
             {{ if .Values.dhcp -}}
             "-dhcp",
             {{ end -}}
+            {{ if .Values.igmp -}}
+            "-igmp",
+            {{ end -}}
             "-c_tag", "{{ .Values.c_tag }}",
             "-c_tag_allocation", "{{ .Values.c_tag_allocation }}",
             "-s_tag", "{{ .Values.s_tag }}",