upgrade for terraform 0.12

[balupton]

https://www.hashicorp.com/blog/announcing-terraform-0-12

for finding out what providers are compatible with 0.12

hashicorp/terraform#21235 (comment)

https://github.com/terraform-providers/terraform-provider-scaleway/issues/125

[balupton]

this should also help

https://www.hashicorp.com/blog/announcing-new-hashicorp-terraform-modules-for-consul-nomad-and-vault

• https://github.com/hashicorp/terraform-aws-consul-starter

• https://github.com/hashicorp/terraform-aws-nomad-starter

• https://github.com/hashicorp/terraform-aws-vault-starter