ERC20Detailed.sol not found in @openzeppelin/contracts/token/ERC20 on GitHub

Support Contracts
7

found sample of overriding decimal but not of overloading, tried:

    constructor(
        string memory name,
        string memory symbol,
        uint256 initialSupply,
        uint8 decimal
    ) public ERC20(name, symbol) {
        // _setupDecimals(6); (not available in 4.x)
        _mint(owner, initialSupply);
    }

deployed Token.deploy('My Token', 'MT6', 1000, 6) but doesn't register on decimals:

      AssertionError: expected 18 to equal 6
      + expected - actual

      -18
      +6