This changes the type of values in Meta for InstanceState to
`interface{}`. They were `string` before.
This will allow richer structures to be persisted to this without
flatmapping them (down with flatmap!). The documentation clearly states
that only primitives/collections are allowed here.
The only thing using this was helper/schema for schema versioning.
Appropriate type checking was added to make this change safe.
The timeout work @catsby is doing will use this for a richer structure.
The schema package provides a high-level interface for writing resource
providers for Terraform.
If you're writing a resource provider, we recommend you use this package.
The interface exposed by this package is much friendlier than trying to
write to the Terraform API directly. The core Terraform API is low-level
and built for maximum flexibility and control, whereas this library is built
as a framework around that to more easily write common providers.