update proto library to google.golang.org/protobuf

[kennethye1]

No description provided.

[kennethye1]

Hmm seems like it will break some stuff. Will double check later.

[trakhimenok]

Should we expect any progress on this any time soon?

[sg0hsmt]

I think the following modifications are necessary for the test to succeed.

• Copy some files from cloud.google.com/go/datastore. refs: datastore: add EnableKeyConversion for compatibility with Cloud Datastore encoded keys #192
  • datastore/internal/cloudkey/cloudkey.go
  • datastore/internal/cloudpb/entity.pb.go
  • v2/datastore/internal/cloudkey/cloudkey.go
  • v2/datastore/internal/cloudpb/entity.pb.go
• Regenerate from all protos using protoc-gen-go with special modifications. ref: fix: regenerate all protos under new namespace #314
  • internal/regen.sh
  • v2/internal/regen.sh

I think there are other fixes that need to be done, but I hope they help you.