Update contact information for cluster-api-provider-packet

- Adds slack channel for cluster-api-provider-packet

Author: detiber

sig-cluster-lifecycle/README.md

@@ -116,6 +116,8 @@ The following [subprojects][subproject-definition] are owned by sig-cluster-life
 ### cluster-api-provider-packet
 - **Owners:**
   - [kubernetes-sigs/cluster-api-provider-packet](https://github.com/kubernetes-sigs/cluster-api-provider-packet/blob/master/OWNERS)
+- **Contact:**
+  - Slack: [#cluster-api-packet](https://kubernetes.slack.com/messages/cluster-api-packet)
 ### cluster-api-provider-vsphere
 - **Owners:**
   - [kubernetes-sigs/cluster-api-provider-vsphere](https://github.com/kubernetes-sigs/cluster-api-provider-vsphere/blob/master/OWNERS)

sigs.yaml

@@ -1085,6 +1085,8 @@ sigs:
     owners:
     - https://raw.githubusercontent.com/kubernetes-sigs/cluster-api-provider-openstack/master/OWNERS
   - name: cluster-api-provider-packet
+    contact:
+      slack: cluster-api-packet
     owners:
     - https://raw.githubusercontent.com/kubernetes-sigs/cluster-api-provider-packet/master/OWNERS
   - name: cluster-api-provider-vsphere