Move version out of SDK. For now it's a copy rather than move: the part not addressed by this change is sdk/helper/useragent.String, which we'll want to remove in favour of PluginString. That will have to wait until we've removed uses of useragent.String from all builtins.
* upgrade vault dependency set
* etcd and grpc issues:
* better for tests
* testing
* all upgrades for hashicorp deps
* kubernetes plugin upgrade seems to work
* kubernetes plugin upgrade seems to work
* etcd and a bunch of other stuff
* all vulnerable packages upgraded
* k8s is broken in linux env but not locally
* test fixes
* fix testing
* fix etcd and grpc
* fix etcd and grpc
* use master branch of go-testing-interface
* roll back etcd upgrade
* have to fix grpc since other vendors pull in grpc 1.35.0 but we cant due to etcd
* rolling back in the replace directives
* a few more testing dependencies to clean up
* fix go mod vendor
* Lower the interval for rotation during tests, to make it more likely
that our five second grace period is sufficient.
* Rewrite to make the rotateCredentials ticker a configurable value.
* 'go mod vendor' for SDK changes.
