[new feature] Tab : support custom color (#1622)

packages/tab/en-US.md

@@ -146,6 +146,7 @@ In swipeable mode, you can switch tabs with swipe gestrue in the content
 | sticky | Whether to use sticky mode | `Boolean` | `false` |
 | offset-top | Offset top when use sticky mode | `Number` | `0` |
 | swipeable | Whether to switch tabs with swipe gestrue in the content | `Boolean` | `false` |
+| color | Set tab's title color | `String` | - |
 
 ### Tab API
 

packages/tab/zh-CN.md

@@ -148,6 +148,7 @@ export default {
 | sticky | 是否使用粘性定位布局 | `Boolean` | `false` |
 | offset-top | 粘性定位布局下与顶部的最小距离 (px) | `Number` | `0` |
 | swipeable | 是否可以滑动内容切换 | `Boolean` | `false` |
+| color | 设置 tab 标题的颜色 | `String` | - |
 
 ### Tab API