Terraform 0.14: vars["cluster_ca_certificate"]: value has marks, so it cannot be serialized

[nick4fake]

With latest Terraform 0.14.1 we see the following issue:

Error: .vars["cluster_ca_certificate"]: value has marks, so it cannot be serialized

(possibly) relevant issue:
hashicorp/terraform#27095

[nick4fake]

BTW, just not to forget, there is also another minor issue:

Warning: Version constraints inside provider configuration blocks are deprecated
k8s/auth.tf line 30, in provider "kubernetes":
  30:   version                = "~> 1.10, != 1.11.0"

Terraform 0.13 and earlier allowed provider version constraints inside the
provider configuration block, but that is now deprecated and will be removed
in a future version of Terraform. To silence this warning, move the provider
version constraint into the required_providers block.

[nick4fake]

Regarding original issue: looks like it is related to a bug in hashicorp/template and has nothing to do with the GKE module itself. I am closing this one.

Looks like https://registry.terraform.io/providers/hashicorp/template/latest is archived so it was my fault for missing that fact.