el-tree在ie9中dhisplay：flex失效

解决方式

<el-tree
        :data="data"
        :props="defaultProps"
        show-checkbox
        node-key="id"
        default-expand-all
        :expand-on-click-node="false"
        :render-content="renderContent"
      ></el-tree>

renderContent(h, { node, data, store }) {
      console.log(node.label);
      console.log(data);
      console.log(store);
      return (
        <div style="display:inline-block;">
          <span style="color:red;">{node.label}</span>
          <span style="color:green;">[1]</span>
        </div>
      );
    }