switch to go vendoring

vendor/github.com/go-micro/plugins/v4/server/grpc/context.go

@@ -0,0 +1,16 @@
+package grpc
+
+import (
+	"context"
+
+	"go-micro.dev/v4/server"
+)
+
+func setServerOption(k, v interface{}) server.Option {
+	return func(o *server.Options) {
+		if o.Context == nil {
+			o.Context = context.Background()
+		}
+		o.Context = context.WithValue(o.Context, k, v)
+	}
+}