Plugin protocol version 6 compatibility with Terraform CLI v1.0.8

@bflad also, for any new resources that we migrate to the Framework, in order to maintain compatibility with 1.0.8, would you recommend to not use NestedAttributes?

This was asked previously here User impact due to Plugin migration from SDKv2 to Plugin Framework and plugin protocol change so we are trying to figure ways we can continue to support Terraform version 1.0.8.