safeApprove of openZeppelin is deprecated

[code423n4]

Handle

robee

Vulnerability details

You use safeApprove of openZeppelin although it's deprecated.
(see https://github.com/OpenZeppelin/openzeppelin-contracts/blob/566a774222707e424896c0c390a84dc3c13bdcb2/contracts/token/ERC20/utils/SafeERC20.sol#L38)
You should change it to increase/decrease Allowance as OpenZeppilin says.
This appears in the following locations in the code base:

    Deprecated safeApprove in TreasuryManager.sol line 78: IERC20(token).approve(ASSET_PROXY, amount); 

[jeffywu]

Duplicate #153

[pauliax]

It is not a duplicate, #153 suggests resetting the approval before setting a new one, and this issue suggests replacing safeApprove with safeIncreaseAllowance/safeDecreaseAllowance.

However, the automated tool that the warden uses marked a wrong code place where this should be applied. Based on my understanding, it should be applied where safeApprove is used:
https://github.com/code-423n4/2022-01-notional/blob/d171cad9e86e0d02e0909eb66d4c24ab6ea6b982/contracts/sNOTE.sol#L82-L83

I am leaving this as a non-critical recommendation.