YIP: Sync Support for Sushiswap YAM/ETH pool

Link to forum: https://forum.yam.finance/t/yip-sync-support-for-sushiswap-yam-eth-pool/615

Basic Summary

We propose to add an additional sync call, on the YAM/ETH (YAMv3) Sushiswap pool, to the Yam rebaser.

Abstract

There is currently an incentivized (via SUSHI rewards) YAMv2/ETH pool on Sushiswap. In order for those incentives to move to the YAM/ETH pool on Sushiswap, the Yam protocol must first call sync on the pool during rebases so it is safe to add liquidity to.

Motivation

The fact that YAMv2 tokens can be used to liquidity mine SUSHI has contributed to the price disparity between YAMv2 and YAM, where the v2 tokens are trading at up to a 50% premium to YAMv2 tokens at times. We are expecting that once this pool is syncd during rebase, Sushiswap will be able to switch their incentives to the YAMv3/ETH pool. This would hopefully bring down the price disparity as well as allow more YAMv2 to migrate and participate in the community and governance. There is, however, no guarantee that Sushiswap will end up incentivizing a YAM/ETH pool, as that is dependent on their governance process.

Specifications

An on-chain governance proposal to call yamRebaser.addSyncPairs([0x95b54c8da12bb23f7a5f6e26c38d04acc6f81820], []) is all that is required for this.