Update fastlane docs and README

[neel1998]

Actual Behaviour
Currently, some of the screenshots in README and fastlane docs are outdated

Expected Behaviour
Make the following changes,

1. Add latest screenshots in fastlane docs and README
2. Add FOSSASIA as author in faslane
3. Update the description in the fast lane (add "This app is proudly developed at FOSSASIA Community")

Would you like to work on the issue?
Yes