Enable GKE pods_per_node flags in GA

[ewolak-sq]

As far as I can tell from the documentation at
https://cloud.google.com/kubernetes-engine/docs/how-to/flexible-pod-cidr,
these features are now GA, so they should be made available in the
"google" provider, not just the "google-beta" provider.

Release Note Template for Downstream PRs (will be copied)

[modular-magician]

Hello! I am a robot who works on Magic Modules PRs.

I have detected that you are a community contributor, so your PR will be assigned to someone with a commit-bit on this repo for initial review. They will authorize it to run through our CI pipeline, which will generate downstream PRs.

Thanks for your contribution! A human will be with you soon.

@slevenick, please review this PR or find an appropriate assignee.

[modular-magician]

Hi! I'm the modular magician, I work on Magic Modules.
I see that this PR has already had some downstream PRs generated. Any open downstreams are already updated to your most recent commit, a3a434c.

Pull request statuses

No diff detected in terraform-provider-google-beta.
No diff detected in terraform-google-conversion.
No diff detected in Ansible.

New Pull Requests

I built this PR into one or more new PRs on other repositories, and when those are closed, this PR will also be merged and closed.
depends: hashicorp/terraform-provider-google#4620
depends: modular-magician/inspec-gcp#227

[rileykarson]

Looks like this is missing some code that needs to be included. I commented all the ones I noticed.

[rileykarson]

The function called here will need to be made available as well.

magic-modules/third_party/terraform/resources/resource_container_cluster.go.erb

Lines 1209 to 1211 in a3a434c

	if cluster.DefaultMaxPodsConstraint != nil {
	d.Set("default_max_pods_per_node", cluster.DefaultMaxPodsConstraint.MaxPodsPerNode)
	}

and the flatten function as well.

And this test (I think all the other features are GA) + the config it links at the bottom of the test file.

magic-modules/third_party/terraform/tests/resource_container_cluster_test.go.erb

Line 1406 in a3a434c

func TestAccContainerCluster_withFlexiblePodCIDR(t *testing.T) {

[rileykarson]

@ndmckinley I saw you just opened #2429, assigning review to you.

[nat-henderson]

Ah, shoot, yeah, I just did essentially the same thing, didn't see your PR. :( I missed doing the same thing in node_pool, though, so I'll make that change in my PR. Thanks.