Use Google Play Billing Library

• Removes ROT-13 encoding of the key from the library, so now you should pass an unencrypted key into the library and handle any key encryption (for protection against disassembly) directly in your app
• Requires a list of subscription keys be passed into the build() method
• Removes the old Google AIDL billing library and switches to the Google Play Billing 3.0 library.
• com.android.vending.BILLING is no longer needed in the Android.manifest file

In one of our apps, we also had to tweak the build.gradle file as follows:

implementation(rootProject.ext.general.inappPayments) {
        // we exclude this, because we already have the 'org.jetbrains:annotations-java5' library that has the same classes
        exclude group: "org.jetbrains", module: "annotations"
    }