Specification non-compliance in JUMPI

The evm crate is a pure Rust implementation of Ethereum Virtual Machine. In evm crate < 0.31.0, JUMPI opcode's condition is checked after the destination validity check. However, according to Geth and OpenEthereum, the condition check should happen before the destination validity check. This is a high severity security advisory if you use evm crate for Ethereum mainnet. In this case, you should update your library dependency immediately to on or after 0.31.0. This is a low severity security advisory if you use evm crate in Frontier or in a standalone blockchain, because there's no security exploit possible with this advisory. It is not recommended to update to on or after 0.31.0 until all the normal chain upgrade preparations have been done. If you use Frontier or other pallet-evm based Substrate blockchain, please ensure to update your spec_version before updating this. For other blockchains, please make sure to follow a hard-fork process before you update this.