MoShitrit: bump alpha k8s versions with May releases

JobBuild
13683
05-26 02:28
pull-kops-e2e-kubernetes-aws 1529650465992609792
pull-kops-verify-boilerplate 1529650466097467392
pull-kops-verify-generated 1529650466026164224
pull-kops-verify-gofmt 1529650466131021824
pull-kops-verify-golangci-lint 1529650466206519296
pull-kops-verify-gomod 1529650466055524352
pull-kops-verify-govet 1529650466168770560