[Feature] Add sixth screenshot to README.

Author: zhanghai

README.md

@@ -15,7 +15,7 @@ An open source Material Design file manager, for Android 5.0+.
 ## Preview
 
 <p><img src="fastlane/metadata/android/en-US/images/phoneScreenshots/1.png" width="32%" /> <img src="fastlane/metadata/android/en-US/images/phoneScreenshots/2.png" width="32%" /> <img src="fastlane/metadata/android/en-US/images/phoneScreenshots/3.png" width="32%" />
-<img src="fastlane/metadata/android/en-US/images/phoneScreenshots/4.png" width="32%" /> <img src="fastlane/metadata/android/en-US/images/phoneScreenshots/5.png" width="32%" /></p>
+<img src="fastlane/metadata/android/en-US/images/phoneScreenshots/4.png" width="32%" /> <img src="fastlane/metadata/android/en-US/images/phoneScreenshots/5.png" width="32%" /> <img src="fastlane/metadata/android/en-US/images/phoneScreenshots/6.png" width="32%" /></p>
 
 ## Features
 

README_zh-CN.md

@@ -13,7 +13,7 @@
 ## 预览
 
 <p><img src="fastlane/metadata/android/en-US/images/phoneScreenshots/1.png" width="32%" /> <img src="fastlane/metadata/android/en-US/images/phoneScreenshots/2.png" width="32%" /> <img src="fastlane/metadata/android/en-US/images/phoneScreenshots/3.png" width="32%" />
-<img src="fastlane/metadata/android/en-US/images/phoneScreenshots/4.png" width="32%" /> <img src="fastlane/metadata/android/en-US/images/phoneScreenshots/5.png" width="32%" /></p>
+<img src="fastlane/metadata/android/en-US/images/phoneScreenshots/4.png" width="32%" /> <img src="fastlane/metadata/android/en-US/images/phoneScreenshots/5.png" width="32%" /> <img src="fastlane/metadata/android/en-US/images/phoneScreenshots/6.png" width="32%" /></p>
 
 ## 特性