cluster_name is case-sensitive

[enoy19]

If the cluster_name contains upper case letters, routes can not be created.

Steps to reproduce:

1. create minimal cluster (follow "usage" part of README.md)

...
module "cluster" {
  source  = "cicdteam/k3s/hcloud"
  version = "0.1.2"
  hcloud_token = var.hcloud_token
  cluster_name = "helloWORLD"
}
...

2. Use cluster_name with lower and uppercase letters e.g. "helloWORLD"
3. terraform apply

---

connect to the master and get all nodes using kubectl get nodes.
describe one node using kubectl describe node <nodename> e.g. kubectl describe node helloworld-cx21-0.

the following error / warning appears:

Events:
  Type     Reason                   Age                    From              Message
  ----     ------                   ----                   ----              -------
  Normal   Starting                 5m26s                  kubelet           Starting kubelet.
  Warning  InvalidDiskCapacity      5m26s                  kubelet           invalid capacity 0 on image filesystem
  Normal   NodeHasSufficientMemory  5m26s (x2 over 5m26s)  kubelet           Node helloworld-master status is now: NodeHasSufficientMemory
  Normal   NodeHasNoDiskPressure    5m26s (x2 over 5m26s)  kubelet           Node helloworld-master status is now: NodeHasNoDiskPressure
  Normal   NodeHasSufficientPID     5m26s (x2 over 5m26s)  kubelet           Node helloworld-master status is now: NodeHasSufficientPID
  Normal   NodeAllocatableEnforced  5m26s                  kubelet           Updated Node Allocatable limit across pods
  Normal   Starting                 5m24s                  kube-proxy        Starting kube-proxy.
  Normal   NodeReady                5m16s                  kubelet           Node helloworld-master status is now: NodeReady
  Warning  FailedToCreateRoute      4m58s                  route_controller  Could not create route 3b2437df-b408-4059-bc3b-5cd304b4abba 10.42.0.0/24 for node helloworld-master after 434.609599ms: hcloud/CreateRoute: hcops/AllServersCache.ByName: hcops/AllServersCache.getCache: not found
  Warning  FailedToCreateRoute      4m48s                  route_controller  Could not create route 3b2437df-b408-4059-bc3b-5cd304b4abba 10.42.0.0/24 for node helloworld-master after 430.176207ms: hcloud/CreateRoute: hcops/AllServersCache.ByName: hcops/AllServersCache.getCache: not found
  Warning  FailedToCreateRoute      4m38s                  route_controller  Could not create route 3b2437df-b408-4059-bc3b-5cd304b4abba 10.42.0.0/24 for node helloworld-master after 573.039188ms: hcloud/CreateRoute: hcops/AllServersCache.ByName: hcops/AllServersCache.getCache: not found
  Warning  FailedToCreateRoute      4m27s                  route_controller  Could not create route 3b2437df-b408-4059-bc3b-5cd304b4abba 10.42.0.0/24 for node helloworld-master after 1.146160095s: hcloud/CreateRoute: hcops/AllServersCache.ByName: hcops/AllServersCache.getCache: not found
  Warning  FailedToCreateRoute      4m14s                  route_controller  Could not create route 3b2437df-b408-4059-bc3b-5cd304b4abba 10.42.0.0/24 for node helloworld-master after 2.801960525s: hcloud/CreateRoute: hcops/AllServersCache.ByName: hcops/AllServersCache.getCache: not found
  Warning  FailedToCreateRoute      4m6s                   route_controller  Could not create route 3b2437df-b408-4059-bc3b-5cd304b4abba 10.42.0.0/24 for node helloworld-master after 501.629225ms: hcloud/CreateRoute: hcops/AllServersCache.ByName: hcops/AllServersCache.getCache: not found
  Warning  FailedToCreateRoute      3m55s                  route_controller  Could not create route 3b2437df-b408-4059-bc3b-5cd304b4abba 10.42.0.0/24 for node helloworld-master after 1.588634126s: hcloud/CreateRoute: hcops/AllServersCache.ByName: hcops/AllServersCache.getCache: not found
  Warning  FailedToCreateRoute      3m47s                  route_controller  Could not create route 3b2437df-b408-4059-bc3b-5cd304b4abba 10.42.0.0/24 for node helloworld-master after 607.737527ms: hcloud/CreateRoute: hcops/AllServersCache.ByName: hcops/AllServersCache.getCache: not found
  Warning  FailedToCreateRoute      3m38s                  route_controller  Could not create route 3b2437df-b408-4059-bc3b-5cd304b4abba 10.42.0.0/24 for node helloworld-master after 240.739195ms: hcloud/CreateRoute: hcops/AllServersCache.ByName: hcops/AllServersCache.getCache: not found
  Warning  FailedToCreateRoute      57s (x16 over 3m27s)   route_controller  (combined from similar events): Could not create route 3b2437df-b408-4059-bc3b-5cd304b4abba 10.42.0.0/24 for node helloworld-master after 1.540429998s: hcloud/CreateRoute: hcops/AllServersCache.ByName: hcops/AllServersCache.getCache: not found