fix: update function_max_instances to null default (#106)

Author: apeabody

README.md

@@ -46,7 +46,7 @@ Then perform the following commands on the root folder:
 | function\_environment\_variables | A set of key/value environment variable pairs to assign to the function. | `map(string)` | `{}` | no |
 | function\_event\_trigger\_failure\_policy\_retry | A toggle to determine if the function should be retried on failure. | `bool` | `false` | no |
 | function\_labels | A set of key/value label pairs to assign to the function. | `map(string)` | `{}` | no |
-| function\_max\_instances | The maximum number of parallel executions of the function. | `number` | `0` | no |
+| function\_max\_instances | The maximum number of parallel executions of the function. | `number` | `null` | no |
 | function\_name | The name to apply to the function | `string` | n/a | yes |
 | function\_runtime | The runtime in which the function will be executed. | `string` | `"nodejs10"` | no |
 | function\_service\_account\_email | The service account to run the function as. | `string` | `""` | no |

test/setup/main.tf

@@ -16,7 +16,7 @@
 
 module "project" {
   source  = "terraform-google-modules/project-factory/google"
-  version = "~> 10.2"
+  version = "~> 14"
 
   name                    = "ci-scheduled-function"
   random_project_id       = "true"

variables.tf

@@ -112,7 +112,7 @@ variable "function_service_account_email" {
 
 variable "function_max_instances" {
   type        = number
-  default     = 0
+  default     = null
   description = "The maximum number of parallel executions of the function."
 }