message: [improvement] Picker: optimize default-index default value
diff: @@ -12,10 +12,7 @@ export default sfc({
  props: {
  ...pickerProps,
  columns: Array,
  - defaultIndex: {
  - type: Number,
  - default: 0
  - },
  + defaultIndex: Number,
  toolbarPosition: {
  type: String,
  default: 'top'
  