Only allow gsk release < 1.30 to use gs tf provider v1

[nvthongswansea]

Error when try to provision a 1.30 cluster in tf provider v1 or upgrade to k8s release 1.30 in v1:

$ tf apply
gridscale_k8s.k8s_cluster: Refreshing state... [id=54bb3416-d591-4c23-9902-6e4c25e1e8d2]
╷
│ Error: this gridscale terraform provider version v1 supports only Kubernetes release < 1.30, for Kubernetes release 1.30.0 please use gridscale terraform provider version v2
│ 
│   with gridscale_k8s.k8s_cluster,
│   on main.tf line 10, in resource "gridscale_k8s" "k8s_cluster":
│   10: resource "gridscale_k8s" "k8s_cluster" {
│ 
╵