fix(transport/grpc/resolver/discovery/resolver.go): remove attributes.Attributes.New() (#2742)

transport/grpc/resolver/discovery/resolver.go

@@ -106,14 +106,9 @@ func (r *discoveryResolver) Close() {
 
 func (r *discoveryResolver) ResolveNow(options resolver.ResolveNowOptions) {}
 
-func parseAttributes(md map[string]string) *attributes.Attributes {
-	var a *attributes.Attributes
+func parseAttributes(md map[string]string) (a *attributes.Attributes) {
 	for k, v := range md {
-		if a == nil {
-			a = attributes.New(k, v)
-		} else {
-			a = a.WithValue(k, v)
-		}
+		a = a.WithValue(k, v)
 	}
 	return a
 }