Add entry for ingress.className in README (goharbor#1832)

Signed-off-by: Pramod Valavala <[email protected]>

README.md

@@ -86,6 +86,7 @@ The following table lists the configurable parameters of the Harbor chart and th
 | `expose.ingress.hosts.core`                                           | The host of Harbor core service in ingress rule                                                                                                                                                                                                                                                                                                                                                                                                                  | `core.harbor.domain`                  |
 | `expose.ingress.controller`                                           | The ingress controller type. Currently supports `default`, `gce`, `alb`, `f5-bigip` and `ncp`                                                                                                                                                                                                                                                                                                                                                                    | `default`                             |
 | `expose.ingress.kubeVersionOverride`                                  | Allows the ability to override the kubernetes version used while templating the ingress                                                                                                                                                                                                                                                                                                                                                                          |                                       |
+| `expose.ingress.className`                                            | Specify the `ingressClassName` used to implement the Ingress (Kubernetes 1.18+)                                                                                                                                                                                                                                                                                                                                                                                  |                                       |
 | `expose.ingress.annotations`                                          | The annotations used commonly for ingresses                                                                                                                                                                                                                                                                                                                                                                                                                      |                                       |
 | `expose.ingress.labels`                                               | The labels specific to ingress                                                                                                                                                                                                                                                                                                                                                                                                                             | {}                                    |
 | `expose.clusterIP.name`                                               | The name of ClusterIP service                                                                                                                                                                                                                                                                                                                                                                                                                                    | `harbor`                              |