Update vendored k8s client code to go-client v4.0.0

[sl1pm4t]

This adds support for Kubernetes 1.7.x according to the client-go [docs].(https://github.com/kubernetes/client-go/tree/master#compatibility-client-go---kubernetes-clusters)

[radeksimko]

Hi @sl1pm4t
thanks a lot for spending the time on this! 👍

I'll make sure it's pulled in as soon as we can to unblock all the other pending PRs.

Just for the sake of transparency:

I firstly want to resolve hashicorp/terraform-provider-google#399, so that I can bump the vendored google provider here to the latest version and fix all the related acceptance test failures which I didn't notice when merging #43

[radeksimko]

I'm going to merge this next week. Thanks for all the work and sorry to keep you waiting!

[sl1pm4t]

Thanks for the update @radeksimko

[radeksimko]

FYI: The main reason this wasn't shipped yet is because I'm trying to figure out why are the following tests failing in 1.7 & 1.8 (passing in 1.6):

TestAccKubernetesPersistentVolumeClaim_googleCloud_importBasic
testing.go:449: Step 0 error: Error applying: 1 error(s) occurred:
	
	* kubernetes_persistent_volume_claim.test: 1 error(s) occurred:
	
	* kubernetes_persistent_volume_claim.test: timeout while waiting for state to become 'Bound' (last state: 'Pending', timeout: 5m0s)

TestAccKubernetesPersistentVolumeClaim_googleCloud_volumeMatch
testing.go:449: Step 0 error: Error applying: 1 error(s) occurred:
	
	* kubernetes_persistent_volume_claim.test: 1 error(s) occurred:
	
	* kubernetes_persistent_volume_claim.test: timeout while waiting for state to become 'Bound' (last state: 'Pending', timeout: 5m0s)
TestAccKubernetesPersistentVolumeClaim_googleCloud_volumeUpdate
testing.go:449: Step 0 error: Error applying: 1 error(s) occurred:
	
	* kubernetes_persistent_volume_claim.test: 1 error(s) occurred:
	
	* kubernetes_persistent_volume_claim.test: timeout while waiting for state to become 'Bound' (last state: 'Pending', timeout: 5m0s)
TestAccKubernetesPersistentVolumeClaim_googleCloud_storageClass
testing.go:449: Step 0 error: Error applying: 1 error(s) occurred:
	
	* kubernetes_persistent_volume_claim.test: 1 error(s) occurred:
	
	* kubernetes_persistent_volume_claim.test: timeout while waiting for state to become 'Bound' (last state: 'Pending', timeout: 5m0s)
	   * ProvisioningFailed: Failed to provision volume with StorageClass "tf-acc-test-szq39zgd63": invalid AccessModes [ReadWriteMany]: only AccessModes [ReadWriteOnce ReadOnlyMany] are supported

If you can help that would be wonderful. 😉 If not, that's 👌 too, I will keep looking.