modify WETH contract call to allow sending in ETH directly

[dapp-whisperer]

The WETH contract allows taking in ETH directly, depositing it to WETH on behalf of the user, using the following function variant which is on the KnightingRound for WETH only

function buyEth(uint8 _daoId, bytes32[] calldata _proof)
        external
        payable
        gacPausable
        returns (uint256 tokenOutAmount_)
    {

Note that the user does not need any token approval to use this function.

Instead, they must send in the ETH amount directly with the function call, in the 'value' field.