[bug report] error in default value of align attribute of El row element

[xlfsummer]

Element UI version

2.15.1

OS/Browsers version

Vue version

2.6.12

Reproduction Link

https://jsfiddle.net/4vwt3mz0/11/

Steps to reproduce

<el-row /> 设置为 type=flex, 其中放置两个不同 size 的 <el-button />

What is Expected?

size 更小的 el-button，其高度应该更小，并且因为 el-row 的 align 属性默认值为 "top", 两个按钮应顶部对齐

What is actually happening?

两个按钮的对齐方式为 strech, 并且显式声明 el-row 的 align 属性为 "top" 也不生效。

其他描述

根据 MDN, align-items 属性的默认值为 normal, 含义如下：

normal
The effect of this keyword is dependent of the layout mode we are in:

• In absolutely-positioned layouts, the keyword behaves like start on replaced absolutely-positioned boxes, and as stretch on all other absolutely-positioned boxes.
• In static position of absolutely-positioned layouts, the keyword behaves as stretch.
• For flex items, the keyword behaves as stretch.
• For grid items, this keyword leads to a behavior similar to the one of stretch, except for boxes with an aspect ratio or an intrinsic sizes where it behaves like start.
  The property doesn't apply to block-level boxes, and to table cells.

代码实现中，当 align 为 top 时, 应将 align-items 属性设置为 flex-start, 而不是忽略：

element/packages/row/src/row.js

Lines 36 to 46 in 0606cb8

	render(h) {
	return h(this.tag, {
	class: [
	'el-row',
	this.justify !== 'start' ? `is-justify-${this.justify}` : '',
	this.align !== 'top' ? `is-align-${this.align}` : '',
	{ 'el-row--flex': this.type === 'flex' }
	],
	style: this.style
	}, this.$slots.default);
	}

[element-bot]

Translation of this issue:

Element UI version

2.15.1

OS/Browsers version

Vue version

2.6.12

Reproduction Link

https://jsfiddle.net/4vwt3mz0/11/

Steps to reproduce

< El row / > 'is set to' type = flex ', where two' < El button / > with different 'size' are placed

What is Expected?

`The height of smaller 'El button' should be smaller, and because the 'align' attribute of 'El row' is' top 'by default, the two buttons should be aligned at the top

What is actually happening?

The alignment of the two buttons is' stretch ', and the explicit declaration that the' align 'attribute of' El row 'is' top' does not take effect.

##Other descriptions
According to [MDN]（ https://developer.mozilla.org/en-US/docs/Web/CSS/align-items ）The default value of the 'align items' attribute is' normal'. The meaning is as follows:

normal
The effect of this keyword is dependent of the layout mode we are in:

• In absolutely-positioned layouts, the keyword behaves like start on replaced absolutely-positioned boxes, and as stretch on all other absolutely-positioned boxes.
• In static position of absolutely-positioned layouts, the keyword behaves as stretch.

• For flex items, the keyword behaves as stretch.
• For grid items, this keyword leads to a behavior similar to the one of stretch, except for boxes with an aspect ratio or an intrinsic sizes where it behaves like start.

The property doesn't apply to block-level boxes, and to table cells.
In code implementation, when 'align' is' top ', the' align items' property should be set to 'flex start', not ignored

element/packages/row/src/row.js

Line 36 in 0606cb8

render(h) {

-L46