YIP-9: Add support for calling sync() on the ETH-YAMv3 Uniswap pool

Summary: This proposal would add functionality to the rebaser to call sync() on the ETH-YAMv3 Uniswap pool during rebase. This would make liquidity added to that pool safe from losing funds during rebase. This proposal does not include any additional incentives to be provided to LPs on this pool.

Reasoning: Due to the fact that Uniswap tracks token balances internally, assets that rebase (like YAM) need to explicitly call sync() during rebase or a portion of the assets pooled can be stolen after rebase. Since ETH is the top pooled asset on Uniswap, it makes sense that we would want to encourage liquidity on the ETH-YAMv3 pool as well. YAMv1 saw people adding liquidity on the YAMv1-ETH pool (>$100k worth at its peak), unknowingly putting those funds at risk.