examples: change xds example to import xds instead of experimental (#3745)

diff --git a/examples/features/xds/client/main.go b/examples/features/xds/client/main.go
index ea50f09..9a67aab 100644
--- a/examples/features/xds/client/main.go
+++ b/examples/features/xds/client/main.go
@@ -31,8 +31,7 @@
 	"google.golang.org/grpc"
 	pb "google.golang.org/grpc/examples/helloworld/helloworld"
 
-	// TODO: change this to xds after the xds package is released.
-	_ "google.golang.org/grpc/xds/experimental" // To install the xds resolvers and balancers.
+	_ "google.golang.org/grpc/xds" // To install the xds resolvers and balancers.
 )
 
 const (