change output syntax

outputs.tf

@@ -1,58 +1,42 @@
 #Module      : VPC
 #Description : Terraform module to create VPC resource on AWS.
 output "vpc_id" {
-  value = concat(
-    aws_vpc.default.*.id
-  )[0]
+  value = join("", aws_vpc.default.*.id)
   description = "The ID of the VPC."
 }
 
 output "vpc_cidr_block" {
-  value = concat(
-    aws_vpc.default.*.cidr_block
-  )[0]
+  value = join("", aws_vpc.default.*.cidr_block)
   description = "The CIDR block of the VPC."
 }
 
 output "vpc_main_route_table_id" {
-  value = concat(
-    aws_vpc.default.*.main_route_table_id
-  )[0]
+  value = join("", aws_vpc.default.*.main_route_table_id)
   description = "The ID of the main route table associated with this VPC."
 }
 
 output "vpc_default_network_acl_id" {
-  value = concat(
-    aws_vpc.default.*.default_network_acl_id
-  )[0]
+  value = join("", aws_vpc.default.*.default_network_acl_id)
   description = "The ID of the network ACL created by default on VPC creation."
 }
 
 output "vpc_default_security_group_id" {
-  value = concat(
-    aws_vpc.default.*.default_security_group_id
-  )[0]
+  value = join("", aws_vpc.default.*.default_security_group_id)
   description = "The ID of the security group created by default on VPC creation."
 }
 
 output "vpc_default_route_table_id" {
-  value = concat(
-    aws_vpc.default.*.default_route_table_id
-  )[0]
+  value = join("", aws_vpc.default.*.default_route_table_id)
   description = "The ID of the route table created by default on VPC creation."
 }
 
 output "vpc_ipv6_association_id" {
-  value = concat(
-    aws_vpc.default.*.ipv6_association_id
-  )[0]
+  value = join("", aws_vpc.default.*.ipv6_association_id)
   description = "The association ID for the IPv6 CIDR block."
 }
 
 output "ipv6_cidr_block" {
-  value = concat(
-    aws_vpc.default.*.ipv6_cidr_block
-  )[0]
+  value = join("", aws_vpc.default.*.ipv6_cidr_block)
   description = "The IPv6 CIDR block."
 }
 
@@ -64,8 +48,6 @@ output "tags" {
 #Module      : INTERNET GATEWAY
 #Description : Terraform internet gateway module output variables.
 output "igw_id" {
-  value = concat(
-    aws_internet_gateway.default.*.id
-  )[0]
+  value = join("", aws_internet_gateway.default.*.id)
   description = "The ID of the Internet Gateway."
 }