const github.com/golang/protobuf/proto.ProtoPackageIsVersion2

2 uses

	github.com/golang/protobuf/proto (current package)
		proto.go#L24: 	ProtoPackageIsVersion2 = true

	github.com/prometheus/client_model/go
		metrics.pb.go#L19: const _ = proto.ProtoPackageIsVersion2 // please upgrade the proto package