Add location arg to bucket backend setup

[tiagovrtr]

Passes location arg through to create_bucket() for backend setup
Solves #12

[tiagovrtr]

@tongueroo if you find useful I can add it to the example in lib/templates/ruby/project/config/terraform/backend.rb.tt

terraform {
  backend "gcs" {
    bucket = "<%%= expansion('terraform-state-:PROJECT-:REGION-:ENV') %>"
    prefix = "<%%= expansion(':TYPE_DIR/:APP/:ROLE/:MOD_NAME/:ENV/:EXTRA/:REGION') %>"
    location = "<%%= expansion(':REGION') %>"
  }
}