* Update protoc version in downloader script
* go get google.golang.org/grpc/cmd/protoc-gen-go-grpc v1.5.1
This matched terraform-plugin-go
* make protobuf
* Run `make protobuf`
* Update generator to handle generic types from google.golang.org/grpc
Looks like this was added in v1.69.3 in https://github.com/grpc/grpc-go/pull/7057 ?
* Run `make generate`
* Fix "cannot infer Res" compile error - more usage of generics
* More fixing compile errors due to switching to use of a generic
* Make putting `google.golang.org/grpc` import into generated files conditional
* Run `make generate`
* Update more places where generics now need to be used
* Update generator to handle any types from google.golang.org/grpc in same switch case.
