feat(google_container_cluster): add resource_labels to node_config

[modular-magician]

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container: added `resource_labels` field to `node_config` resource

Description

Enable resource labels on node_config so they can be used in node pools.
https://cloud.google.com/kubernetes-engine/docs/how-to/creating-managing-labels#create-node-pool-labels

resource "google_container_node_pool" "np_with_node_config" {
  name               = "test-nodepool"
  location           = "us-central1-a"
  cluster            = "test-cluster"
  initial_node_count = 1
  node_config {
    machine_type = "g1-small"
    min_cpu_platform = "Intel Broadwell"
    resource_labels = {
      "key1" = "value1"
      "key2" = "value2"
    }

Fixes #13064

Derived from GoogleCloudPlatform/magic-modules#6842

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