https://github.com/code-423n4/2022-03-biconomy/blob/main/contracts/hyphen/token/TokenManager.sol#L49-L53
https://github.com/code-423n4/2022-03-biconomy/blob/main/contracts/hyphen/token/TokenManager.sol#L91-L98
As per the title, the addSupportedToken() allows for zero equilibriumFee or maxFee to be set, but changeFee() doesnt.
Either include non-zero checks in addSupportedToken() or remove them in changeFee().
