Update go mod and vendor in client dir to 0.28.0

client/vendor/k8s.io/apimachinery/pkg/runtime/codec.go

@@ -45,7 +45,6 @@ func NewCodec(e Encoder, d Decoder) Codec {
 
 // Encode is a convenience wrapper for encoding to a []byte from an Encoder
 func Encode(e Encoder, obj Object) ([]byte, error) {
-	// TODO: reuse buffer
 	buf := &bytes.Buffer{}
 	if err := e.Encode(obj, buf); err != nil {
 		return nil, err