Also check Filesystem::pathExists() in case the binary is local, for example <project root>/vendor/bin/phpcs
It might be worth mentioning that this was tested on windows.

composer require --dev squizlabs/php_codesniffer, then edit composer.json and add

"config": {
    "bin-dir": "bin"
},

Then in .arclint add:

"phpcs": {
    "type": "phpcs",
    "include": "(\\.php$|\\.inc$)",
    "bin": "vendor/bin/phpcs"
}

and run arc lint.