Publish X-Ray on F-Droid

[SecUpwN]

Good morning, @duo-labs developers, thanks for open sourcing X-Ray! I'd like to see X-Ray on F-Droid. See how to add it and feel free to add the following F-Droid badge to your README once it got accepted:

• Badge to copy and paste to your README when X-Ray finally got added to F-Droid:

[![F-Droid](https://upload.wikimedia.org/wikipedia/commons/thumb/0/0d/Get_it_on_F-Droid.svg/320px-Get_it_on_F-Droid.svg.png)](https://f-droid.org/repository/browse/?fdid=com.duosecurity.x_ray "X-Ray on F-Droid")

Since X-Ray was previously closed source, I am currently using VTS for Android. As you can see, they are also coping with AndroidVTS/android-vts#38. Maybe you can help them to land on F-Droid as well?