Revert "Use gradle 5.3" hoping it helps with https://github.com/jitpack/jitpack.io/issues/3788
Revert "Use gradle 5.3" hoping it helps with https://github.com/jitpack/jitpack.io/issues/3788

This reverts commit 794a2529e1a691ce67be2d255424bfc9b2846a2e.

walleth/kethereum