b0g0_ctf - user (smart contract) can deposit ether and not get the NFT due to _mint function

[IkiliagwuC]

Impact: smart contracts interacting as users may not receive NFT

Description
in the deposit function _mint is used instead of _safeMint

        require(msg.value == depositRequired, "Incorrect ETH amount");

        _tokenIds.increment();
        uint256 newTokenId = _tokenIds.current();

        deposits[msg.sender] += msg.value;

        _mint(msg.sender, newTokenId);
    }

user can be a smart contract address which correctly implements the onERC721Received method, but it will not be called and tokens may be subsequently trapped.

solution : use _safeMint instead of _mint

[BogoCvetkov]

Use of _mint is intentional. Readme for this contest state:

Assume depositors are the ones responsible for taking care that they can handle NFT's.