Upgrade kubernetes dependencies to 0.25.2

[elijahomolo]

https://jira.internal.digitalocean.com/browse/CON-7651

go get k8s.io/client-go@v0.25.2
go mod tidy
go mod vendor

• the lint job has been removed from CI in favor of the vet job.
• The apiVersion batchv1beta has been deprecated and updated to batchv1