Update dependencies to Vault 1.1.2

[lawliet89]

Fixes #333

I ran

go get -u github.com/hashicorp/[email protected]
go mod tidy
go get -u github.com/hashicorp/[email protected]
go get -u github.com/hashicorp/vault/[email protected]

Non-cloud related tests pass.

The Vault Changelog for the next release says:

Go Modules change: Vault now uses Go Modules to manage dependencies. As a result to both reduce transitive dependencies for API library users and plugin authors, and to work around various conflicts, we have moved various helpers around, mostly under an sdk/ submodule. A couple of functions have also moved from plugin helper code to the api/ submodule. If you are a plugin author, take a look at some of our official plugins and the paths they are importing for guidance.

Not sure what this entails. @tyrannosaurus-becks ?

[tyrannosaurus-becks]

Thanks @lawliet89 !