Change `uint` to `uint256` (#1160)
Change `uint` to `uint256` (#1160)

This is a minor change, aligning to the same convention used in the other contracts.
OpenZeppelin/zep-solidity,OpenZeppelin/zeppelin-solidity,OpenZeppelin/openzeppelin-contracts,OpenZeppelin/zep-solidity,OpenZeppelin/openzeppelin-contracts,OpenZeppelin/zeppelin-solidity,OpenZeppelin/openzeppelin-contracts