Use distributionSha256Sum for Verification of downloaded Gradle #613
Description
Add distributionSha256Sum to gradle-wrapper.properties file at: https://github.com/horizontalsystems/bitcoin-kit-android/blob/38611c8e8ae03bdbb119de722de0554096eab3a2/gradle/wrapper/gradle-wrapper.properties
more info: https://docs.gradle.org/current/userguide/gradle_wrapper.html#sec:verification
checksum value can be taken from: https://gradle.org/release-checksums/