deprecate outdated syntax (#56)

Co-authored-by: zjhe <hezijie@microsoft.com>

Author: lonegunmanb

.tflint_alt.hcl

@@ -133,7 +133,7 @@ rule "terraform_comment_syntax" {
 }
 
 rule "terraform_deprecated_index" {
-  enabled = false
+  enabled = true
 }
 
 rule "terraform_deprecated_interpolation" {

main.tf

@@ -37,7 +37,7 @@ resource "azurerm_lb" "azlb" {
     name                          = var.frontend_name
     private_ip_address            = var.frontend_private_ip_address
     private_ip_address_allocation = var.frontend_private_ip_address_allocation
-    public_ip_address_id          = var.type == "public" ? join("", azurerm_public_ip.azlb.*.id) : ""
+    public_ip_address_id          = try(azurerm_public_ip.azlb[0].id, "")
     subnet_id                     = var.frontend_subnet_id
   }
 }
@@ -83,5 +83,5 @@ resource "azurerm_lb_rule" "azlb" {
   backend_address_pool_ids       = [azurerm_lb_backend_address_pool.azlb.id]
   enable_floating_ip             = false
   idle_timeout_in_minutes        = 5
-  probe_id                       = element(azurerm_lb_probe.azlb.*.id, count.index)
+  probe_id                       = element(azurerm_lb_probe.azlb[*].id, count.index)
 }

outputs.tf

@@ -15,22 +15,22 @@ output "azurerm_lb_id" {
 
 output "azurerm_lb_nat_rule_ids" {
   description = "the ids for the azurerm_lb_nat_rule resources"
-  value       = azurerm_lb_nat_rule.azlb.*.id
+  value       = azurerm_lb_nat_rule.azlb[*].id
 }
 
 output "azurerm_lb_probe_ids" {
   description = "the ids for the azurerm_lb_probe resources"
-  value       = azurerm_lb_probe.azlb.*.id
+  value       = azurerm_lb_probe.azlb[*].id
 }
 
 output "azurerm_public_ip_address" {
   description = "the ip address for the azurerm_lb_public_ip resource"
-  value       = azurerm_public_ip.azlb.*.ip_address
+  value       = azurerm_public_ip.azlb[*].ip_address
 }
 
 output "azurerm_public_ip_id" {
   description = "the id for the azurerm_lb_public_ip resource"
-  value       = azurerm_public_ip.azlb.*.id
+  value       = azurerm_public_ip.azlb[*].id
 }
 
 output "azurerm_resource_group_name" {