Element Plus tree-select component minor feature enhance

Based on Element Plus tree-select component, multiple select within group, but single select between group.

Enhance props

// multiple select within group, but single select between group
singleBetweenGroup: {
    type: Boolean,
    default: false
}

Notice !!!
Devloped under auhtor's team business requirement, just promise it run normally under tree data that has only two level.

npm install ev_tree_select
import css : import 'ev_tree_select/dist/style.css'
import into your single vue file component : import { EVTreeSelect } from 'ev_tree_select';

Basic usage and more attributes/props/method please reference Elment-plus