Byzantine validator can cause network crash by broadcasting big round vote message

[b00f]

Description

A byzantine validator can create a vote message with a big round value (up to maxint16) and broadcast it to the network. This can cause honest nodes to crash, as they extend the roundMessages slice to accommodate the vote message, eventually exhausting available memory.

Expected Behavior

To prevent this issue, the blockchain should reject any vote message with a round value that is more than 2 rounds bigger than the current round. This will prevent byzantine validators from causing network crashes and ensure the stability of the blockchain.