Migrate to AndroidX

[TylerCarberry]

https://developer.android.com/jetpack/androidx/migrate

Also update dependencies

• Android Gradle 3.1.4 --> 3.5.3
• Gradle Wrapper 4.9 --> 5.4.1
• Support Library 27.1.1 --> AppCompat 1.1.0
• Espresso 3.0.2 --> 3.2.0

[ened]

This is a important PR. When can it be merged @alexey0xdc @vitkuzmenko ?

[ranganatha2g]

are any of these PR's be merged anytime soon? Thanks

[ghost]

Any update here?

[ghost]

One of the most important changes. Hope it will be merged this year :-)

[pcrds]

Hello @TylerCarberry and thanks for this PR. It's great to see that someone is not only downloading the source but also contributes.
It's been a long time while there is no maintainer for Android version and that's why your PR was not yet tested & merged. Are you still using pay.cards? May be you could maintain this for a while?

[TylerCarberry]

Thanks for the offer but I am not interested in maintaining this library