Add support for CPU Platform in google_container_node_pool (hashicorp#622)

* update container/v1 API

* add support for CPU Platform in `google_container_node_pool`

* fix broken links

Author: davidquarles

docs/r/container_cluster.html.markdown

@@ -159,6 +159,12 @@ which the cluster's instances are launched
     are preemptible. See the [official documentation](https://cloud.google.com/container-engine/docs/preemptible-vm)
     for more information. Defaults to false.
 
+* `min_cpu_platform` - (Optional) Minimum CPU platform to be used by this instance.
+    The instance may be scheduled on the specified or newer CPU platform. Applicable
+    values are the friendly names of CPU platforms, such as `Intel Haswell`. See the
+    [official documentation](https://cloud.google.com/compute/docs/instances/specify-min-cpu-platform)
+    for more information.
+
 **Addons Config** supports the following addons:
 
 * `http_load_balancing` - (Optional) The status of the HTTP Load Balancing

docs/r/container_node_pool.html.markdown

@@ -114,6 +114,12 @@ resource "google_container_cluster" "primary" {
     are preemptible. See the [official documentation](https://cloud.google.com/container-engine/docs/preemptible-vm)
     for more information. Defaults to false.
 
+* `min_cpu_platform` - (Optional) Minimum CPU platform to be used by this instance.
+    The instance may be scheduled on the specified or newer CPU platform. Applicable
+    values are the friendly names of CPU platforms, such as `Intel Haswell`. See the
+    [official documentation](https://cloud.google.com/compute/docs/instances/specify-min-cpu-platform)
+    for more information.
+
 The `autoscaling` block supports:
 
 * `min_node_count` - (Required) Minimum number of nodes in the NodePool. Must be >=1 and