Neutron v4.2.1-testnet Upgrade, Instructions

--- title: Neutron v4.2.1-testnet Upgrade order: 2 --- <!-- markdown-link-check-disable -- Chain upgrade point: 22th of August 15:30 UTC at height 18256000 Go version: v1.22 Release: https://github.com/neutron-org/neutron/releases/tag/v4.2.1-testnet This document describes the st…