Solidityでselfdestructをしたいのですがエラーがでます。

SolidityをRemix上で書いていてselfdestructを使いたいのですが、
『TypeError: Invalid type for argument in function call. Invalid implicit conversion from address to address payable requested.
selfdestruct(owner); // send ether to address inside parenthis』というエラーが出てしまいます。
^---^
どうしたらよいでしょうか。

pragma solidity ^0.5.0;

contract Owned{
address public owner;

modifier onlyOwner() {
    require(msg.sender == owner);
    _;
}

function owned() internal {
    owner = msg.sender;
}

function changeOwner(address _newOwner) public onlyOwner {
    owner = _newOwner;
}

}

contract Mortal is Owned {

function kill() public onlyOwner {
selfdestruct(owner); // send ether to address inside parenthis
}
}

contract  MortalSample is Mortal {

string public someState;
function() payable external {

}

constructor() public{
    owned();
    someState = "initial";
}
}