Bump go-grpc-middleware to v2

[AlejoAsd]

Context

Closes #20.

We're using go-grpc-middleware to provide a set of gRPC interceptors for net.Servers. We're still using go-grpc-middleware/v1, which is quite old and has caused issues with some downstream applications that use gz-go.

Changes

Most of the changes required to migrate from v1 to v2 required updating package addresses and minor modification of some interceptors.

Interceptors

A number of default interceptors had to be updated because they were deprecated, moved or updated.

• grpc_ctxtags was removed from go-grpc-middleware as a new internal mechanism is now available for different interceptors to communicate. The interceptor was removed from the set of default interceptors.
• grpc_opentracing was removed from go-grpc-middleware in favor of OTel implementations. The tracing interceptor package was replaced by the google.golang.org/grpc/otelgrpc package.
• Other existing interceptors had their packages updated to match the new package structure imposed by go-grpc-middleware, but no other changes were necessary.

Additional changes

• grpc_middleware.ChainUnaryServer was removed from go-grpc-middleware as the grpc package introduced grpc.ChainUnaryInterceptor to do the same thing.
  • GenerateStreamServerInterceptorsChainWithBase and GenerateStreamServerInterceptorsChainWithBase were updated to use the new grpc methods. These methods now return ServerOptions instead of a slice of interceptors.
  • NewServerOptionsGRPC was updated to call the modified methods directly, as opposed to wrapping them with grpc.Stream/UnaryInterceptor([...]) since the inner function now returns a ServerOption and no conversion is necessary.
• The testing go-grpc-middleware/testing and go-grpc-middleware/testing/testproto packages were merged into a single go-gprc/middleware/v2/testing/testpb package. All references to these packages were updated.
• The go-grpc-middleware/util/metautils package was reorganized and is now part of the go-grpc-middleware/metadata package.