Fix "list" warning

Terraform 0.11 and earlier required type constraints to be given in quotes,
but that form is now deprecated and will be removed in a future version of
Terraform. To silence this warning, remove the quotes around "list" and write
list(string) instead to explicitly indicate that the list elements are
strings.

Author: ddosia

modules/bastion/variables.tf

@@ -58,7 +58,7 @@ variable "associate_public_ip_address" {
 
 variable "allow_ssh_cidrs" {
   description = "List Cidrs from where ssh is to be allowed for bastion host. Default is anywhere"
-  type        = "list"
+  type        = list
   default     = ["0.0.0.0/0"]
 }
 

modules/network.tf

@@ -67,7 +67,7 @@ variable "bastion_host_keypair" {
 
 variable "bastion_host_allow_ssh_cidrs" {
   description = "List Cidrs from where ssh is to be allowed for bastion host. Default is anywhere"
-  type        = "list"
+  type        = list
   default     = ["0.0.0.0/0"]
 }
 

modules/spare-subnet/variables.tf

@@ -6,10 +6,10 @@ variable "vpc_id" {}
 
 variable "spare_subnets" {
   description = "A list of CIDR blocks for spare subnets inside the VPC."
-  type        = "list"
+  type        = list
 }
 
 variable "azs" {
   description = "A list of Availability zones in the region"
-  type        = "list"
+  type        = list
 }