use the index (#1138)

src/terraform/modules/cachewarmer_build/outputs.tf

@@ -20,5 +20,5 @@ output "cachewarmer_manager_bootstrap_script_path" {
 
 output "module_depends_on_id" {
   description = "the id(s) to force others to wait"
-  value = null_resource.build_cachewarmer_bootstrap.id
+  value = null_resource.build_cachewarmer_bootstrap[0].id
 }

src/terraform/modules/cachewarmer_manager_install/outputs.tf

@@ -1,4 +1,4 @@
 output "module_depends_on_id" {
   description = "the id(s) to force others to wait"
-  value = null_resource.install_cachewarmer_manager.id
+  value = null_resource.install_cachewarmer_manager[0].id
 }

src/terraform/modules/cachewarmer_submitjob/outputs.tf

@@ -1,4 +1,4 @@
 output "module_depends_on_id" {
   description = "the id(s) to force others to wait"
-  value = null_resource.cachewarmer_submitjob.id
+  value = null_resource.cachewarmer_submitjob[0].id
 }