update type for WaitGroup in server

server/options.go

@@ -13,6 +13,7 @@ import (
 	"go.unistack.org/micro/v4/meter"
 	"go.unistack.org/micro/v4/options"
 	"go.unistack.org/micro/v4/register"
+	msync "go.unistack.org/micro/v4/sync"
 	"go.unistack.org/micro/v4/tracer"
 	"go.unistack.org/micro/v4/util/id"
 )
@@ -32,7 +33,7 @@ type Options struct {
 	// Listener may be passed if already created
 	Listener net.Listener
 	// Wait group
-	Wait *sync.WaitGroup
+	Wait *msync.WaitGroup
 	// TLSConfig specifies tls.Config for secure serving
 	TLSConfig *tls.Config
 	// Metadata holds the server metadata