Allow metallb:speaker to create events (#6147)

Since MetalLB v0.8[1], metallb:speaker has started publishing an event
nodeAssigned on k8s resource.
To support MetalLB v0.8+, this allows metallb:speaker to create events.

[1]: 5cc6e23776 (diff-60053ad6fecb5a3cfabb6f3d9e720899R246)

contrib/metallb/roles/provision/templates/metallb.yml.j2

@@ -50,6 +50,9 @@ rules:
 - apiGroups: [""]
   resources: ["services", "endpoints", "nodes"]
   verbs: ["get", "list", "watch"]
+- apiGroups: [""]
+  resources: ["events"]
+  verbs: ["create"]
 {% if podsecuritypolicy_enabled %}
 - apiGroups: ["policy"]
   resourceNames: ["metallb"]