chore: add 2.5.1 changelog

CHANGELOG.en-US.md

 ## Changelog
 
+### 2.5.1
+
+*2019-01-26*
+
+#### Optimization
+- DatePicker: highlight current month and year (by @Debiancc in #14211)
+- Update 2.5.0 changelog (by @wacky6 in #14217)
+
+#### Bug fixes
+- Fix export issue generate by webpack upgrading (by @island205 in #14220)
+- Keep 2.4.11 docs && new sub folder for 2.5+ (by @iamkun in #14222)
+
 ### 2.5.0
 
 *2019-01-25*

CHANGELOG.es.md

 ## Changelog
 
+### 2.5.1
+
+*2019-01-26*
+
+#### Optimization
+- DatePicker: highlight current month and year (by @Debiancc in #14211)
+- Update 2.5.0 changelog (by @wacky6 in #14217)
+
+#### Bug fixes
+- Fix export issue generate by webpack upgrading (by @island205 in #14220)
+- Keep 2.4.11 docs && new sub folder for 2.5+ (by @iamkun in #14222)
+
 ### 2.5.0
 
 *2019-01-25*

CHANGELOG.zh-CN.md

 ## 更新日志
 
+### 2.5.1
+
+*2019-01-26*
+
+#### 优化
+- DatePicker：添加月、年高亮的样式（by @Debiancc in #14211）
+- 更新 2.5.0 changelog （by @wacky6 in #14217）
+
+
+#### 修复
+- 修复升级 Webpack 4 产生的问题，无法具名 `import` 组件，`ELEMENT.locale()` 调用报错。（by @island205 in #14220）
+- 恢复 2.4.11 文档 (by @iamkun in #14222)
+
+
 ### 2.5.0
 
 *2019-01-25*