feat: add update_interval and update_interval_when_expecting (#1173)

## Description

It seems that the default values set by GitLab are not perfect. I often
saw rate limiting on the AWS API for autoscaling. Making these variables
configurable ensures to stay below the limits. These variable have the
same defaults as documented by GitLab:
https://docs.gitlab.com/runner/configuration/advanced-configuration.html#the-runnersautoscaler-section

The best values depend on how many Runners you have deployed.

## Verification

None

main.tf

@@ -127,6 +127,10 @@ locals {
       runners_capacity_per_instance = 1
       runners_max_use_count         = var.runner_worker_docker_autoscaler.max_use_count
       runners_max_instances         = var.runner_worker.max_jobs
+
+      runners_update_interval                = var.runner_worker_docker_autoscaler.update_interval
+      runners_update_interval_when_expecting = var.runner_worker_docker_autoscaler.update_interval_when_expecting
+
       runners_autoscaling = [for config in var.runner_worker_docker_autoscaler_autoscaling_options : {
         for key, value in config :
         # Convert key from snake_case to PascalCase which is the casing for this section.

template/runner-docker-autoscaler-config.tftpl

@@ -3,6 +3,9 @@
     plugin = "fleeting-plugin-aws"
 
     capacity_per_instance = ${runners_capacity_per_instance}
+    update_interval = ${runners_update_interval}
+    update_interval_when_expecting = ${runners_update_interval_when_expecting}
+
     max_use_count = ${runners_max_use_count}
     max_instances = ${runners_max_instances}
 

variables.tf

@@ -607,12 +607,16 @@ variable "runner_worker_docker_autoscaler" {
     connector_config_user = User to connect to worker machine
     key_pair_name = The name of the key pair used by the Runner to connect to the docker-machine Runner Workers. This variable is only supported when `enables` is set to `true`.
     max_use_count = Max job number that can run on a worker
+    update_interval = The interval to check with the fleeting plugin for instance updates.
+    update_interval_when_expecting = The interval to check with the fleeting plugin for instance updates when expecting a state change.
   EOT
   type = object({
-    fleeting_plugin_version = optional(string, "1.0.0")
-    connector_config_user   = optional(string, "ec2-user")
-    key_pair_name           = optional(string, "runner-worker-key")
-    max_use_count           = optional(number, 100)
+    fleeting_plugin_version        = optional(string, "1.0.0")
+    connector_config_user          = optional(string, "ec2-user")
+    key_pair_name                  = optional(string, "runner-worker-key")
+    max_use_count                  = optional(number, 100)
+    update_interval                = optional(string, "1m")
+    update_interval_when_expecting = optional(string, "2s")
   })
   default = {}
 }