64bit Android builds

Play store will require new submissions to be 64bit builds in near future:

https://android-developers.googleblog.com/2017/12/improving-app-security-and-performance.html

• In the second half of 2018, Play will require that new apps and app updates target a recent Android API level. This will be required for new apps in August 2018, and for updates to existing apps in November 2018. This is to ensure apps are built on the latest APIs optimized for security and performance.
• In August 2019, Play will require that new apps and app updates with native libraries provide 64-bit versions in addition to their 32-bit versions.