Add readme for imagePullSecrets

Signed-off-by: Louis Haußknecht <[email protected]>

multicluster/charts/linkerd-multicluster/README.md

@@ -92,6 +92,7 @@ Kubernetes: `>=1.21.0-0`
 | gateway.tolerations | list | `[]` | Tolerations for the gateway pod |
 | identityTrustDomain | string | `"cluster.local"` | Identity Trust Domain of the certificate authority |
 | imagePullPolicy | string | `"IfNotPresent"` | Docker imagePullPolicy for all multicluster components |
+| imagePullSecrets | list | `[]` | For Private docker registries, authentication is needed.  Registry secrets are applied to the respective service accounts |
 | linkerdNamespace | string | `"linkerd"` | Namespace of linkerd installation |
 | linkerdVersion | string | `"linkerdVersionValue"` | Control plane version |
 | namespaceMetadata.image.name | string | `"extension-init"` | Docker image name for the namespace-metadata instance |