zAuction - unclear upgrade path
`zAuction` appears to implement an upgrade path for the auction system via `zAuctionAccountant`. `zAuction` itself does not hold any value. The `zAuctionAccountant` can be configured to allow only one `zAution` contract to interact with it. The update of the contract reference takes effect immediately (https://github.com/ConsenSys/zer0-zauction-audit-2021-05/issues/7).\\nAcceptance of bids via the accountant on the old contract immediately fail after an admin updates the referenced `zAuction` contract while `WETH` bids may still continue. This may create an unfavorable scenario where two contracts may be active in parallel accepting `WETH` bids.\\nIt should also be noted that 2nd layer bids (signed data) using the accountant for the old contract will not be acceptable anymore.\\n```\\nfunction SetZauction(address zauctionaddress) external onlyAdmin{\\n    zauction = zauctionaddress;\\n    emit ZauctionSet(zauctionaddress);\\n}\\n```\\n
Consider re-thinking the upgrade path. Avoid keeping multiple versions of the auction contact active.
```\\nfunction SetZauction(address zauctionaddress) external onlyAdmin{\\n    zauction = zauctionaddress;\\n    emit ZauctionSet(zauctionaddress);\\n}\\n```\\n