add fastlane for F-Droid (#6)

* add fastlane for F-Droid

* Update full_description.txt

* add screenshots

Co-authored-by: linsui <linsui555@gmail.com>
Co-authored-by: 源文雨 <41315874+fumiama@users.noreply.github.com>

fastlane/metadata/android/en-US/full_description.txt

@@ -0,0 +1,7 @@
+Third-party client for copymanga with better reading/downloading experience.
+<h3>Features</h3>
+1. Browse homepage, category, rank, my downloads, tag, and author.
+2. View, search and read manga; log reading progress.
+3. Download manga. But due to force majeure, the downloading is slow and error-prone. This is not due to bad optimization, absolutely not.
+4. Read downloaded manga.
+5. Check update.

fastlane/metadata/android/en-US/short_description.txt

@@ -0,0 +1 @@
+Third-party client for copymanga with better reading/downloading experience

fastlane/metadata/android/zh-CN/full_description.txt

@@ -0,0 +1,7 @@
+拷贝漫画的第三方 APP，优化阅读/下载体验
+<h3>功能</h3>
+1. 浏览主页、分类、排行、我的下载、标签、作者。
+2. 查看、搜索漫画并直接阅读；记录漫画与章节的阅读进度。
+3. 下载漫画。但是由于不可抗力，下载速度较慢且容易出错，这绝对不是优化的原因，绝对不是。
+4. 阅读下载的漫画。
+5. 检查更新。

fastlane/metadata/android/zh-CN/short_description.txt

@@ -0,0 +1 @@
+拷贝漫画的第三方 APP，优化阅读/下载体验