Update tests to match the fix in mitchellh/cli#71, which aligns MockUi
with BasicUi and allows newlines in user input.
We are not using the new ErrorWriter, added in mitchellh/cli#81, as it
does not appear to interact correctly with panicwrap. All error output
from CLI parsing will continue to appear on stdout, not stderr.
Terraform 0.13 will allow the installation of providers from various
sources. If a user updates their configuration to change the source of
an in-use provider (for example, if the provider namespace changes),
they will also need to update the state file accordingly.
This commit introduces a new `state replace-provider` subcommand which
supports this. All resources using the `from` provider will be updated
to use the `to` provider.
Alisdair McDiarmid