Adopt Terraform v0.12 templatefile function

* Update terraform-render-bootstrap module to adopt the
Terrform v0.12 templatefile function feature to replace
the use of terraform-provider-template's `template_dir`
* Require Terraform v0.12.6+ which adds `for_each`

Background:

* `template_dir` was added to `terraform-provider-template`
to add support for template directory rendering in CoreOS
Tectonic Kubernetes distribution (~2017)
* Terraform v0.12 introduced a native `templatefile` function
and v0.12.6 introduced native `for_each` support (July 2019)
that makes it possible to replace `template_dir` usage

CHANGES.md

@@ -4,6 +4,9 @@ Notable changes between versions.
 
 ## Latest
 
+* Require Terraform version v0.12.6+ (action required)
+  * Replace internal usage of `template_dir` with `templatefile` function
+
 ## v1.16.3
 
 * Kubernetes [v1.16.3](https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG-1.16.md#v1163)

aws/container-linux/kubernetes/bootstrap.tf

@@ -1,6 +1,6 @@
 # Kubernetes assets (kubeconfig, manifests)
 module "bootstrap" {
-  source = "git::https://github.com/poseidon/terraform-render-bootstrap.git?ref=0daa1276c633fea28e41b2c2c18831e2584deb24"
+  source = "git::https://github.com/poseidon/terraform-render-bootstrap.git?ref=1bba891d95b143866614c928f87026e4c79f2eae"
 
   cluster_name          = var.cluster_name
   api_servers           = [format("%s.%s", var.cluster_name, var.dns_zone)]

aws/container-linux/kubernetes/versions.tf

@@ -1,7 +1,7 @@
 # Terraform version and plugin versions
 
 terraform {
-  required_version = "~> 0.12.0"
+  required_version = "~> 0.12.6"
   required_providers {
     aws      = "~> 2.23"
     ct       = "~> 0.3"

aws/fedora-coreos/kubernetes/bootstrap.tf

@@ -1,6 +1,6 @@
 # Kubernetes assets (kubeconfig, manifests)
 module "bootstrap" {
-  source = "git::https://github.com/poseidon/terraform-render-bootstrap.git?ref=0daa1276c633fea28e41b2c2c18831e2584deb24"
+  source = "git::https://github.com/poseidon/terraform-render-bootstrap.git?ref=1bba891d95b143866614c928f87026e4c79f2eae"
 
   cluster_name          = var.cluster_name
   api_servers           = [format("%s.%s", var.cluster_name, var.dns_zone)]

aws/fedora-coreos/kubernetes/versions.tf

@@ -1,7 +1,7 @@
 # Terraform version and plugin versions
 
 terraform {
-  required_version = "~> 0.12.0"
+  required_version = "~> 0.12.6"
   required_providers {
     aws      = "~> 2.23"
     ct       = "~> 0.4"

azure/container-linux/kubernetes/bootstrap.tf

@@ -1,6 +1,6 @@
 # Kubernetes assets (kubeconfig, manifests)
 module "bootstrap" {
-  source = "git::https://github.com/poseidon/terraform-render-bootstrap.git?ref=0daa1276c633fea28e41b2c2c18831e2584deb24"
+  source = "git::https://github.com/poseidon/terraform-render-bootstrap.git?ref=1bba891d95b143866614c928f87026e4c79f2eae"
 
   cluster_name = var.cluster_name
   api_servers  = [format("%s.%s", var.cluster_name, var.dns_zone)]

azure/container-linux/kubernetes/versions.tf

@@ -1,7 +1,7 @@
 # Terraform version and plugin versions
 
 terraform {
-  required_version = "~> 0.12.0"
+  required_version = "~> 0.12.6"
   required_providers {
     azurerm  = "~> 1.27"
     ct       = "~> 0.3"

bare-metal/container-linux/kubernetes/bootstrap.tf

@@ -1,6 +1,6 @@
 # Kubernetes assets (kubeconfig, manifests)
 module "bootstrap" {
-  source = "git::https://github.com/poseidon/terraform-render-bootstrap.git?ref=0daa1276c633fea28e41b2c2c18831e2584deb24"
+  source = "git::https://github.com/poseidon/terraform-render-bootstrap.git?ref=1bba891d95b143866614c928f87026e4c79f2eae"
 
   cluster_name                    = var.cluster_name
   api_servers                     = [var.k8s_domain_name]

bare-metal/container-linux/kubernetes/versions.tf

@@ -1,7 +1,7 @@
 # Terraform version and plugin versions
 
 terraform {
-  required_version = "~> 0.12.0"
+  required_version = "~> 0.12.6"
   required_providers {
     matchbox = "~> 0.3.0"
     ct       = "~> 0.3"

bare-metal/fedora-coreos/kubernetes/bootstrap.tf

@@ -1,6 +1,6 @@
 # Kubernetes assets (kubeconfig, manifests)
 module "bootstrap" {
-  source = "git::https://github.com/poseidon/terraform-render-bootstrap.git?ref=0daa1276c633fea28e41b2c2c18831e2584deb24"
+  source = "git::https://github.com/poseidon/terraform-render-bootstrap.git?ref=1bba891d95b143866614c928f87026e4c79f2eae"
 
   cluster_name                    = var.cluster_name
   api_servers                     = [var.k8s_domain_name]

bare-metal/fedora-coreos/kubernetes/versions.tf

@@ -1,7 +1,7 @@
 # Terraform version and plugin versions
 
 terraform {
-  required_version = "~> 0.12.0"
+  required_version = "~> 0.12.6"
   required_providers {
     matchbox = "~> 0.3.0"
     ct       = "~> 0.4"

digital-ocean/container-linux/kubernetes/bootstrap.tf

@@ -1,6 +1,6 @@
 # Kubernetes assets (kubeconfig, manifests)
 module "bootstrap" {
-  source = "git::https://github.com/poseidon/terraform-render-bootstrap.git?ref=0daa1276c633fea28e41b2c2c18831e2584deb24"
+  source = "git::https://github.com/poseidon/terraform-render-bootstrap.git?ref=1bba891d95b143866614c928f87026e4c79f2eae"
 
   cluster_name = var.cluster_name
   api_servers  = [format("%s.%s", var.cluster_name, var.dns_zone)]

digital-ocean/container-linux/kubernetes/versions.tf

@@ -1,7 +1,7 @@
 # Terraform version and plugin versions
 
 terraform {
-  required_version = "~> 0.12.0"
+  required_version = "~> 0.12.6"
   required_providers {
     digitalocean = "~> 1.3"
     ct           = "~> 0.3"

google-cloud/container-linux/kubernetes/bootstrap.tf

@@ -1,6 +1,6 @@
 # Kubernetes assets (kubeconfig, manifests)
 module "bootstrap" {
-  source = "git::https://github.com/poseidon/terraform-render-bootstrap.git?ref=0daa1276c633fea28e41b2c2c18831e2584deb24"
+  source = "git::https://github.com/poseidon/terraform-render-bootstrap.git?ref=1bba891d95b143866614c928f87026e4c79f2eae"
 
   cluster_name          = var.cluster_name
   api_servers           = [format("%s.%s", var.cluster_name, var.dns_zone)]

google-cloud/container-linux/kubernetes/versions.tf

@@ -1,7 +1,7 @@
 # Terraform version and plugin versions
 
 terraform {
-  required_version = "~> 0.12.0"
+  required_version = "~> 0.12.6"
   required_providers {
     google       = "~> 2.5"
     ct           = "~> 0.3"