docs - Update k8s compat matrix (hashicorp#20714)

Update compatibility matrix

website/content/docs/k8s/compatibility.mdx

@@ -15,6 +15,7 @@ Consul Kubernetes versions all of its components (`consul-k8s` CLI, `consul-k8s-
 
 | Consul version | Compatible `consul-k8s` versions | Compatible Kubernetes versions | Compatible OpenShift versions          |
 | -------------- | -------------------------------- | -------------------------------| -------------------------------------- |
+| 1.18.x         | 1.4.x                            | 1.26.x - 1.29.x                | 4.12.x - 4.14.x (4.15.x not available) |
 | 1.17.x         | 1.3.x                            | 1.25.x - 1.28.x                | 4.12.x - 4.14.x (4.15.x not available) |
 | 1.16.x         | 1.2.x                            | 1.24.x - 1.27.x                | 4.11.x - 4.14.x                        |
 | 1.15.x         | 1.1.x                            | 1.23.x - 1.26.x                | 4.10.x - 4.13.x                        |
@@ -41,7 +42,7 @@ Starting with Consul K8s 0.39.0 and Consul 1.11.x, Consul Kubernetes supports th
 
 ### Red Hat OpenShift
 
-You can enable support for Red Hat OpenShift by setting `enabled: true` in the `global.openshift` stanza. Refer to the [Deploy Consul on RedHat OpenShift tutorial](https://developer.hashicorp.com/consul/tutorials/kubernetes/kubernetes-openshift-red-hat) for instructions on deploying to OpenShift. 
+You can enable support for Red Hat OpenShift by setting `enabled: true` in the `global.openshift` stanza. Refer to the [Deploy Consul on RedHat OpenShift tutorial](https://developer.hashicorp.com/consul/tutorials/kubernetes/kubernetes-openshift-red-hat) for instructions on deploying to OpenShift.
 
 ### VMware Tanzu Kubernetes Grid and Tanzu Kubernetes Grid Integrated Edition