Created using remix-ide: Realtime Ethereum Contract Compiler and Runtime. Load this file by pasting this gists URL or ID at https://remix.ethereum.org/#version=soljson-v0.8.0+commit.c7dfd78e.js&optimize=false&runs=200&gist=

contracts...CompateAbiEncodePackedAndBytes.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract CompateAbiEncodePackedAndBytes {

    function execute1() public {
        require(test1());
    }

    function execute2() public {
        require(test2());
    }

    function test1() public pure returns (bool) {
        return keccak256(abi.encodePacked("string")) == keccak256(abi.encodePacked("string"));
    }

    function test2() public pure returns (bool) {
        return keccak256(bytes("string")) == keccak256(bytes("string"));
    }

}

this gist is for this blog post.
https://qiita.com/taijusanagi/items/b26732c3cb5cf931428f