chore: add changelog 4.2.4

Author: QingWei-Li

CHANGELOG.md

@@ -1,3 +1,18 @@
+<a name="4.2.4"></a>
+## [4.2.4](https://github.com/QingWei-Li/docsify/compare/v4.2.2...v4.2.4) (2017-07-26)
+
+
+### Bug Fixes
+
+* **render:** Remove getRootNode to be compatible with the lower version of Chrome, fixed [#225](https://github.com/QingWei-Li/docsify/issues/225) ([b8dd346](https://github.com/QingWei-Li/docsify/commit/b8dd346))
+
+
+### Features
+
+* **search:** Supports the max depth of the search headline, fixed [#223](https://github.com/QingWei-Li/docsify/issues/223), resolve [#129](https://github.com/QingWei-Li/docsify/issues/129) ([b7b589b](https://github.com/QingWei-Li/docsify/commit/b7b589b))
+
+
+
 <a name="4.2.3"></a>
 ## [4.2.3](https://github.com/QingWei-Li/docsify/compare/v4.2.2...v4.2.3) (2017-07-26)