message: [improvement] Dialog: improve accessibility
diff: @@ -127,7 +127,12 @@ export default sfc({
  return (
  <transition name="van-dialog-bounce">
  - <div vShow={this.value} class={[bem(), this.className]}>
  + <div
  + vShow={this.value}
  + role="dialog"
  + aria-labelledby={title || message}
  + class={[bem(), this.className]}
  + >
  {Title}
  {Content}
  {ButtonGroup}
  