[Feature] Update changelog for translation import.

fastlane/metadata/android/en-US/changelogs/21.txt

@@ -1,4 +1,5 @@
 - The Material Design 1 theme has been deprecated and will be removed in the next major release. This reduces code complexity and maintenance burden, meanwhile allows new features including AMOLED dark theme, alternative colors for the MD2 theme and outlined icons.
+- Added Italian and Japanese translations.
 - Fixed crash when viewing large images.
 - Fixed certain issues when picking files.
 - Fixed certain issues in FTP server.

fastlane/metadata/android/zh-CN/changelogs/21.txt

@@ -1,4 +1,5 @@
 - 质感设计 1 主题已被弃用，并将在下个大版本中被移除。这有利于降低代码复杂度和维护成本，并且使得 AMOLED 黑色主题、质感设计 2 主题色选择和轮廓图标等功能成为可能。
+- 添加了意大利语和日语翻译。
 - 修复了在查看大图片时的崩溃。
 - 修复了选取文件时的多个问题。
 - 修复了 FTP 服务器的多个问题。